High efficiency dehumidification system and method

ABSTRACT

This document describes a high efficiency dehumidification system (HEDS) and method of operating the same. The HEDS systems and physical implementations can include a variety of equipment, such as fans, filtration systems, fluid-conveying coils, piping or tubing, heat transfer coils, vents, louvers, dampers, valves, fluid chillers, fluid heaters, or the like. Any of the implementations described herein can also include controls and logic, responsive to one or more sensors or other input devices, for controlling the equipment for each implementation described herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to U.S. Provisional PatentApplication No. 62/634,621, filed Feb. 23, 2018, and titled “HighEfficiency Dehumidification System and Method,” the entirety of which isincorporated by reference herein.

BACKGROUND

Existing coil and dehumidification unit designs commonly implemented forcooling, dehumidification and reheat duties have a number of drawbacks.

Common problems created by industry standard cooling coil, cooling unit,cooling systems and HVAC designs include, but are not limited to: highairside pressure drop; excessive cooling coil vertical height thatcreates a condensate “stacking” effect; inadequate numbers of coil rowscan create a condensate stacking effect; inadequate and poorly designedcooling coil drain pans; excessive air velocity across the coil sectionsduring deep dehumidification duties; excessive liquid water (condensate)being carried off of the coil into the unit and downstream ductwork; andcondensate carry-off being re-evaporated into the airstream; condensatebeing carried off and re-evaporated off of the cooling coil and drainpan systems due to compressor cycling on and off; condensate beingcarried off and re-evaporated off of the cooling coil and drain pansystems due to temperature swings; inability to unload far enough toprovide proper temperature and RH control when loads are light; energywaste, excessive water and chemical consumption; excessive energyrejection to, or withdrawal from, ground coupled HVAC systems;undersized ductwork and air distribution terminal units; and othercommon system design and operational problems.

High airside air pressure drop across the coils, usually between 0.8inches of water column and 1.2 inches of water column contribute toenergy waste, condensate carry off from the coils, and systemoperational and performance problems. Excessive coil vertical height,which creates a condensate “stacking” effect, whereby the condensate isbeing produced at a faster rate than it can be drained out of the coilsurface area can create or contribute to a number of problems.Condensate can partially or completely block the airflow throughsignificant area of the coil, so little or no air passes through thewater-logged coil section and heat transfer between the air and thecooling fluid contained within the cooling coil tubing is minimized.

Major HVAC equipment manufacturers do not seem to be aware of thissituation —they rate the capacity of a 4′ tall coil the same as theyrate the capacity of two 2′ tall coils. In the real world, theperformance is not the same. Design engineers routinely size their coilsat greater than 450 feet per minute, with most designs being above 500feet per minute and even up to and higher than 550 feet per minute facevelocities across the heat transfer surface area.

When sections of a coil finned surface area become partially or fullywater saturated with condensed moisture, several negative things happen.The air velocity through that section of the coil are reduced, or evendropped to zero, due to the added air pressure drop across the coilcaused by the condensed water being held in the coil heat transfer finpack. When the air velocity through that section of the coil is reduceddue to the higher air pressure drop through that section caused by thewater being held in the finned surface area of the coil, the air thatdoes pass through that section of the coil has more contact time withthe finned heat transfer area of the coil, so a greater level ofcondensate generation per CFM of airflow occurs through that coilsection, making the condensate problem worse.

When the air velocity through one section of a coil is reduced due topartial or full water saturation of that coil section, the air velocitythrough the remaining coil face area must be increased in order todeliver the same volume of air from the unit. The higher air velocitythrough the coil causes the air pressure drop through the cooling coilto increase significantly. This higher airflow/coil face velocity canincrease to the point that the condensed water is actually blown orpulled off of the coil and into the unit and downstream ductwork oroccupied spaces. The higher air pressure drop can cause the fan powerdraw to increase, wasting energy, or, if it is a constant air volume(CAV) fan with no means to control air flow as systems pressure dropsrise and fall, the actual air flow rate being delivered to the spaceswill be decreased. In hospitals and other critical facilities that relyon constant air flows to maintain pressure relationships, this can causelife-threatening problems.

Air velocities that are too high, or that are higher than design airvelocities, negatively impact the performance of Ultraviolet GermicidalIrradiation (UVGI), Photo Catalytic Oxidation (PCO) and otherchemical-biological mitigation measures as air contact time with thetechnologies is minimized. Air contact time is important to many ofthese technologies.

When the airflow through a coil section is partially or completelyblocked, the cooling fluid on the inside of the coil heat transfertubing is not coming in contact with the air (load) via the finned heatexchanger surface area to the extent required to properly andeffectively transfer heat from the air in contact with the finnedsurface area to the chilled fluid contained inside the coil tubing.Accordingly, the chilled fluid temperature rise can be reduced in asignificant manner, creating energy waste and operational problems onseveral levels.

This problem can be a big contributor to the “Low Delta T Syndrome”. TheLow Delta T Syndrome exists when the chilled fluid temperaturedifferential between the fluid being supplied and the fluid beingreturned to the cooling plant is less than the design temperaturedifferential, and can cause significant energy waste in the chillerplant and overall HVAC systems, and this problem, in and of itself, cancontribute to mold growth in the equipment, ductwork and facility.

In the case of an excessive condensate flow rate actually blockingairflow through a section of a coil, there is zero heat transfer betweenthe air and the chilled fluid contained within the coil tubing, sincethere is no air in contact with the finned surface area of the coilwhere it is water saturated. The chilled fluid inside the tubing isessentially only in heat transfer contact with condensed water on theexterior of the coil, so the chilled fluid is only cooling condensatedown, and the condensate is about to be sent into the condensate drainsystem. No useful work will occur in that section of the coil, and infact it is very detrimental to HVAC system operations. The condensate isalready very cold, so the chilled fluid inside the heat transfer tubingthat is in contact with the condensate may only experience a temperaturerise of 1° F. to 3° F., vs. a typical design temperature rise of 10° F.to 16° F.

A higher chilled fluid flow rate is required for several reasons—thereis a greater dehumidification load than required, due to the need tosub-cool air to deliver the required cooling capacity to the loads.Further, latent cooling requires a higher chilled fluid flow rate thansensible cooling. A potentially significant portion of the chilled fluidflow through the coil is experiencing a very low temperaturedifferential and doing near zero effective work with the chilled fluid.

When a section of a coil is partially or fully blocked by condensatestacking, the air velocity increases through the remaining coil surfacearea. Coil air pressure drop is an essentially squared function with airface velocity through a coil, so if the bottom 8″ of a 48″ tall coilbank are saturated with condensed moisture, the face velocity throughthe remaining coil area can be increased by a factor of(48″/(48″−8″))=1.2. The air pressure drop is a squared function of that,so, (1.2){circumflex over ( )}2=1.44, or a 44% increase in the airpressure drop can occur. A 0.8″ air pressure drop coil has just become a1.15″ air pressure drop coil, which can either require more fan energy,or reduce the amount of air available to cool the space if the fansystem cannot provide the design airflow through the coil at that higherair pressure drop.

In this example, the coil is losing approximately 20% of the availableair flow area, so the air flow velocity through the coil has increasedby approximately 20%. There is a high likelihood that condensed moisturewill be carried off of this coil, starting very near the top of thecoil, all the way down to where the condensed moisture water blockageoccurs.

If the higher air pressure drop through the coil section cannot beaccommodated by higher fan speeds and higher fan energy to blow therequired amount of air into the HVAC system, the amount of coolingcapacity at that supply air temperature setpoint can be inadequate tomeet the needs of the loads. The standard solution to not having enoughair flow to cool a space is to reduce the supply air temperaturesetpoint to try to meet the loads with a lower volume of colder air.

Reducing the supply air temperature setpoint can make the condensedwater carry-off and low chilled fluid system temperature differentialproblems even worse. As the supply air temperature setpoint is reduced,a higher volume of chilled fluid must be circulated through the coil,and even more condensate can be created due to the lower average chilledfluid temperatures inside the coil tubing and at the coil finned heattransfer surface. This increased amount of condensate can further reducethe coil finned area that is available to cool the air, which createshigher air velocities through the coils, which then causes a greatervolume of condensate to be carried off of the coils. A lower airtemperature setpoint will require an even higher volume of chilledfluid, and the higher chilled fluid volumes will result in an even lowerchilled fluid temperature differential. Thus, the problem compoundsitself.

Industry standard cooling coil and cooling unit designs further includethe problem of high air pressure drop of air filters downstream of thecooling coil system(s) causing wasted fan energy, as well ascondensation of moisture in the filter bank.

In many applications, post-AHU air filtration is required by Codeauthorities, or by the needs of the process that is being served by theAHU. In typical designs, the air filters exhibit a very high air facevelocity, and a corresponding high air pressure drop. As the air filtersdo their job, they filter dirt and other particles and life forms out ofthe air, which further increases the air pressure drop through the airfilters. A dirty air filter can exhibit an air pressure drop that is twoto three times greater than the clean filter air pressure drop. When airexperiences a drop in pressure, a drop in temperature accompanies thispressure drop. When air temperature is reduced, condensation can forminside the air filters and downstream from the air filters if the airwas close to the dewpoint temperature. This can occur even if there isno condensate being carried off of the cooling coils.

Additionally, there are no perfectly tuned HVAC control systems, orchiller and compressor equipment, so temperature cycling (swings) canand do occur. Chiller compressors and DX systems that have stages ofcapacity, rather than fully modulated control down to 0% loads can anddo abruptly change chilled water supply temperatures which affects AHUsupply air temperatures as the staging up and down occurs, chillers andcompressors with various forms of unloading or capacity control, such ashot gas bypass, can exhibit erratic temperature control, even changes inthe condensing temperature and pressure can change chiller capacity andchiller supply water temperatures. When chillers or compressors arestaged on and off, the plant leaving water temperatures or AHU supplyair temperatures can change to a great degree. Some control systems aredesigned to allow the CHWS temperature or AHU supply air temperature toincrease by several degrees before another stage of cooling is added.Control valves and thermal expansion valves and electronic expansionvalves for heat transfer coils are rarely tuned to cover the entirebreadth of operating conditions that are experienced—they may be tunedfor full load, and not perform well at low loads or vice versa. All ofthese things and many others, conspire to create temperature swings inthe supply air temperature leaving the AHU's. When the air temperatureis below setpoint, the equipment, filters, ductwork, insulating systemsand the like are all driven to a low temperature. When the airtemperature swings above setpoint, less dehumidification occurs, andeven re-humidification from water in the coil fin pack and drain pan,and when the warmer, wetter air comes in contact with the colder surfaceareas, if the dewpoint temperature of the air is above the surfacetemperature of the equipment, filters, ductwork, insulation systems,etc., condensation will occur.

Industry standard cooling coil and cooling unit designs further includethe problem of excessive chilled fluid volume flow rates being requiredfor dehumidification duties. Typically sized and designed cooling coilsrequire significantly greater volumes of chilled fluid to meetdehumidification needs. This creates a “Low Delta T Syndrome” withsignificant negative energy and capital cost consequences.

The inherent design of DX systems makes them relatively poor atperforming latent cooling duties. Many DX based air conditioning systemsuse 3 or 4 row cooling coils, and relatively high air velocities, whichare both detrimental to meeting latent cooling loads.

A substantial amount of cooling coil surface area must be dedicated tocreating “superheat”. Superheat is heat added to the refrigerant, afterit has been evaporated and turned into a gas, and is required to ensurethat liquid refrigerant, in any form, never makes it back to thecompressor.

For these reasons, DX based systems have even less effective surfacearea for latent cooling than would be expected because of their fewerrows and higher air velocities.

Further problems include high approach temperatures between the coolingfluid leaving the coil and the air temperature entering the coolingcoil. This creates energy waste and unstable temperature control in realworld applications.

Smaller coils with less heat transfer liquid thermal mass are much moresusceptible to temperature swings than larger coils. A “typical” coilmay have 75% less heat transfer fluid mass when compared to coilsdescribed herein.

Other problems include: potential mismatch between the amount ofsensible and latent cooling needed for dehumidification duties; numbersof rows of coil tubing and finned heat exchanger surface are typicallyinadequate for dehumidification duties; or undersized and improperlydesigned coils require a high approach temperature between the airentering the coil and the water leaving the coil.

As coils and their heat transfer fins age, corrosion, dirt andbiological growth can further degrade performance that was most likelyinadequate in the first place, so the problems become worse over time.This can create situations where control systems are unable to maintainstable dry bulb temperature, dew point temperature and relative humiditycontrol.

Most installed cooling/dehumidification systems do not operate well orconsistently at low loads, especially with high pressure/temperaturedifferentials between the refrigerant suction pressure/temperature andthe refrigerant condensing pressure/temperature. These conditions arecalled low load/high lift conditions. Under low load/high liftconditions, the compressors need to be “false loaded” to a verysignificant degree to keep them operational and stable, but many/mostHVAC systems are not equipped with an effective means to add load to thecompressor while still maintaining proper temperature/RH/load control.Some compressors cannot unload effectively below 30% to 40% capacity,even when the cooling/dehumidification load being presented to them is10% or lower. This causes several undesirable things to occur. Mostinstalled DX based compressors for homes, apartments, hotels, barracksetc. have single stage capacity control, the compressor is either on, orit is off, with capacity control being provided by the refrigerantexpansion valves, but the compressor is still running at full speed.

Conventional HVAC systems might use a typical air cooled, directexpansion (DX), single zone, single compressor, HVAC design operating ona humid day, under less than 100% continuous load conditions, which iswhere it will run 99% of the time during the dehumidification season.The compressor(s) is (are) controlled based on a thermostat, or combinedthermostat/humidistat to maintain conditions in the spaces being served.If the temperature or humidity exceeds the desired setpoint, thecompressor can be started and cooling/dehumidification process willstart.

With a typical HVAC design, the built-in controls contain an“anti-recycle timer” which keeps the compressor from experiencing toomany start/stop cycles per hour to protect the equipment from damage,motor over-heating and the like. They are also equipped with built insafeties that look at the refrigerant temperatures and pressures and thesafeties will shut the compressors off if the evaporator refrigerantpressure/temperature gets too low/cold, or if the condenserpressure/temperature gets too high/hot.

The typical HVAC system design in this example stages the compressor onand off for capacity control and it is not equipped with Hot Gas By-Pass(HGBP). For this example, assume that there is a 1 degree dead band thatcontrols the start/stop for the compressor. This means that thecompressor can be started 1° F. above the thermostat setpoint andstopped when the temperature is 1° F. lower than the thermostatsetpoint, so if the thermostat setpoint was 72° F., the compressor wouldstart at 73° F. and shut down when the temperature dropped to 71° F., a2° F. temperature swing.

Using an average cooling load of 50%, the compressor can be running forapproximately 50% of the time, and off for approximately 50% of thetime. Compressor staging based capacity control is like trying toaverage 50 MPH on the freeway by driving 100 MPH for 5 minutes, thenslamming on the brakes and being stopped for 5 minutes, then repeatingthe process continually. If the system is equipped with only athermostat, which is typically the case, here is how the systemoperation will appear:

As an example, starting from compressor startup, the space temperaturecan be at 73° F. and the space can be humid. Since the only form ofcooling capacity control is via starting and stopping the compressor,the compressor is providing 100% capacity against a 50% load. The excesscapacity overcools the air in the ductwork, and condenses significantvolumes of water out of the air onto the cooling coil. Within the spanof 5 to 10 minutes, the space temperature will have dropped to the lowersetpoint limit and will be shut down. The fan can be running to meetventilation, pressurization, make-up air or other requirements. Sincethere is no cooling capacity coming from the compressor, and there issignificant condensate buildup on the cooling coils, the warmreturn/mixed air that is being passed through the cooling coilimmediately starts to re-evaporate the water from the cooling coils anddrain pans and re-injecting that moisture into the equipment, ductworkand facility. Since the ductwork and air distribution system wassubcooled, moisture can start to condense inside the air distributionsystem, even on and under the insulation system, creating an environmentthat allows biological growth to occur. Additionally, the space is beingre-humidified by the warm moist air that is coming off of the coolingcoils when the compressor cycles off. Additional energy will have to beexpended again, to remove moisture that was just removed a few momentsago.

If the system is equipped with a thermostat and a humidistat, whichcould be the case for a space with RH (Relative Humidity) controlstrategies, here is how the system operation will appear: Operation canbe similar to the thermostat-only design, but the humidistat willtypically try to keep the compressor running longer, as the intermittentoperation of the compressor, and the re-humidification process thatoccurs every time the compressor cycles off does not allow the RH to beproperly controlled.

In an attempt to lower the RH of the space being controlled, thecompressor will stay running longer, and will over-cool the air to agreater extent, and the compressor will likely get cycled off when therefrigerant safeties detect that the refrigerant is too cold. The makesthe problems described above even worse. The spaces can be over-cooled,which can actually increase the space RH and increase the chances forcondensation to occur in the conditioned spaces. The ductwork and airdistribution system can be over-cooled, creating the potential for evengreater condensation inside the HVAC system when the compressor cyclesoff and the condensate re-evaporation, re-humidification process startsto occur.

If the system is equipped with Hot Gas By-Pass (HGBP), as may be thecase for larger systems, here is how the system operation would be inthis example: If the hot refrigerant gas is injected into therefrigerant distributor, there is a high potential for the supply airtemperature control to be lost—the air temperature leaving the coolingcoil can be higher than required to perform dehumidification duties.This leads to a myriad of problems. This is discussed in greater detaillater in this application.

In most conventional systems, condensed moisture (water) getsre-evaporated off of the cooling coils when the cooling coil capacity iscycled off or temperature swings occur for any reason. The relativehumidity control effectiveness of direct expansion (DX) can be verypoor, unless the unit is on and running at 100% capacity. Similarly,many chilled water based cooling systems do not properly control RH,which can cause mold growth.

SUMMARY

This document presents high efficiency dehumidification systems, highefficiency cooling and heating plant systems, systems that allow precisetemperature and RH control even down to very low loads, systems thatextend or enhance the capacity, efficiency and viability ofground-sourced heat pumps and their earth-sourced cooling and heatingenergy storage, capacity and efficiency, and methods of controlling,optimizing and operating the same.

In some aspects, a high efficiency dehumidification system for an airhandling unit (AHU) is disclosed. The system include a cooling coilhaving an inlet to receive chilled liquid at a first temperature from acooling plant to cool air that passes over the cooling coil, and havingan outlet to output spent chilled liquid at a second temperature, thesecond temperature being greater than the first temperature due to heatexchange from the air to the chilled liquid. The system further includesa first fluid conduit having an input connected with the output of thecooling coil, the first fluid conduit further having an output junctionhaving first and second outputs, and a cooling recovery coil having aninlet connected with the first output of the output junction of thefirst fluid conduit to receive at least a portion of the spent chilledliquid at about the second temperature. In some aspects, the coolingrecovery coil includes an outlet to return the spent chilled liquid fromthe cooling recovery coil to the cooling plant, a remaining portion ofthe spent chilled liquid bypassing the cooling recovery coil via thesecond output of the output junction of the first fluid conduit andreturning to the cooling plant. In still some aspects, the systemfurther includes a second fluid conduit having a plurality of inputs,the plurality of inputs including at least one input connected with eachof the first and second outputs of the output junction, the second fluidconduit further having an output to return the spent chilled liquid tothe cooling plant. The system further can further include a controlvalve on the second fluid conduit to control a flow rate of the spentchilled liquid from the cooling recovery coil to the cooling plant.

In yet other aspects, a high efficiency dehumidification system for afan coil unit for providing heat transfer to building is disclosed. Thesystem includes a preheat coil for receiving a preheating liquid fromone or more heat recovery units to preheat air that passes over thepreheat coil, and a cooling coil having an inlet to receive chilledliquid at a first temperature from a heat pump to cool the preheated airthat passes over the cooling coil, and having an outlet to output spentchilled liquid at a second temperature, the second temperature beinggreater than the first temperature due to heat exchange from the air tothe chilled liquid. The system can further include a first fluid conduithaving an input connected with the outlet of the cooling coil and anoutlet. The system can further includes a cooling recovery coil havingan inlet connected with the outlet of the first fluid conduit to receiveat least a portion of the spent chilled liquid at about the secondtemperature, and having an outlet to return the spent chilled liquidfrom the cooling recovery coil to the cooling plant. The system canfurther include a second fluid conduit having an input connected withthe first and second outputs of the output junction, the second fluidconduit further having an output to return the spent chilled liquid tothe heat pump. In some aspects, the system can further include a reheatcoil having an inlet from the heat pump and the one or more heatrecovery units, and an outlet to the one or more heat recovery units, tocontrol a temperature of the air from the cooling recovery coil.

Systems are presented that can control temperatures and relativehumidity at cooling loads down to 0% load, in an efficient, stable andreliable manner. In yet other aspects, any of the systems describedherein can include a control system to evaluate input data representingone or more variables, and to determine one or more outputs to controlthe system to control the one or more variables.

Additional options such as Ultraviolet Germicidal Irradiation (UVGI),Photocatalytic Oxidation (PCO), alternate heating or reheating sources,and after-filters are shown. A unique benefit of HEDS that is notavailable with other systems is that the lower air velocities designedinto HEDS units provides significantly longer contact time between UVGI,PCO, chemical/biological risk mitigation systems, heating, reheating andfiltration systems, which can significantly improve their effectiveness.Humidifiers can also be installed for loads that must maintain minimumRH levels.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features and advantages can beapparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described in detail with referenceto the following drawings.

FIG. 1 illustrates a failsafe cooling coil and cooling recovery coilsystem for a multi-unit structure;

FIG. 2 illustrates a system that is similar to the system illustrated inFIG. 1 with failsafe operation, but does not use any form of a controlvalve to modulate capacity;

FIG. 3 is similar to the system illustrated in FIG. 2 with failsafeoperation, but with added functionality;

FIG. 4 is similar to the system illustrated in FIG. 1 with failsafeoperation, but with added functionality;

FIG. 5 is similar to the system illustrated in FIG. 4 with failsafeoperation, but including a fixed or adjustable automatic flow controlvalve (AFCV);

FIG. 6 is similar to the system illustrated in FIG. 1 with failsafeoperation, but with added functionality;

FIG. 7 illustrates a system that is similar to the system illustrated inFIG. 6 with failsafe operation, but does not use any form of a controlvalve to modulate capacity;

FIG. 8 illustrates a failsafe cooling coil and cooling recovery coilsystem for a single unit structure;

FIG. 9 is similar to the system illustrated in FIG. 1 with failsafeoperation, but with added functionality;

FIG. 10 is similar to the system illustrated in FIG. 1 with failsafeoperation, but using a fixed or variable setpoint differential pressurecontrol valve to bypass water around the CRC when the flow rates climb;

FIG. 11 is similar to the system illustrated in FIG. 10 with failsafeoperation, but having a fixed or adjustable automatic flow control valve(FCV or AFCV);

FIG. 12 is similar to the system illustrated in FIG. 1 with failsafeoperation;

FIG. 13 depicts one form of a HEDS implementation that is similar toFIG. 1 with failsafe operation, but does not use any form of a controlvalve to modulate capacity;

FIG. 14 depicts a system that is similar to FIG. 13 with failsafeoperation, but is depicted providing HVAC services for multiple AHUs;

FIG. 15 depicts a system that is similar to FIG. 13 , with failsafeoperation, but with added functionality;

FIG. 16 depicts a system that is similar to FIG. 15 with failsafeoperation, but is depicted providing HVAC services for multiple AHUs;

FIG. 17 is similar to the system illustrated in FIG. 13 with failsafeoperation, but does not use any form of a control valve to modulatecapacity;

FIG. 18 is similar to the system illustrated in FIG. 17 with failsafeoperation, but is depicted providing HVAC services for multiple AHUs;

FIG. 19 is similar to the system illustrated in FIG. 17 with failsafeoperation, but with added functionality;

FIG. 20 is similar to the system illustrated in FIG. 18 with failsafeoperation, but with added functionality;

FIGS. 21-23 depict a cooling/heating plant based on a modified heat pumpdesign (or standard chiller-based design) that is built to providerelative humidity control, even down to 0% cooling loads, whileenhancing the capacity of the earth-coupled field to which it isattached;

FIG. 24A depicts an abbreviated system architecture for the controlsystem sequences of operation;

FIG. 24B depicts an abbreviated system architecture for the controlsystem sequences of operation;

FIGS. 25A-25B illustrates depictions of an AHU coil configuration toextend the operational life of the AHU coil consistent withimplementations of the current subject matter;

FIGS. 26A-26B illustrates depictions of an AHU coil configuration toextend the operational life of the AHU coil consistent withimplementations of the current subject matter;

FIGS. 27A-27B illustrates depictions of an AHU coil configuration toextend the operational life of the AHU coil consistent withimplementations of the current subject matter;

FIGS. 28A-28B illustrates depictions of an AHU coil configuration toextend the operational life of the AHU coil consistent withimplementations of the current subject matter;

FIGS. 29-31 illustrate improved systems for distributing cleaning andflushing agents into a coil system consistent with implementations ofthe current subject matter;

FIGS. 32-36 illustrate various coil configurations consistent withimplementations of the current subject matter;

FIGS. 37-50 illustrate various coil fin configurations consistent withimplementations of the current subject matter;

FIGS. 51-64 illustrate various condensate management air handling unitconfigurations consistent with implementations of the current subjectmatter;

FIGS. 65-66 are variations of a condensate management system consistentwith implementations of the current subject matter;

FIGS. 67-68 show example coil circuiting consistent with implementationsof the current subject matter; and

FIG. 69 shows an improved heat transfer fin design consistent withimplementations of the current subject matter.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

This document describes a high efficiency dehumidification systems(HEDS), condensate management systems, coil cleaning systems, andmethods of operating the same. These systems described herein mayaddress one or more of the disadvantages described above. The systemsconsistent with implementations of the current subject matter describedherein may dehumidify air passing through the systems as a result of theconfigurations described herein, but may be used in otherimplementations. The HEDS systems and physical implementations caninclude a variety of equipment, such as fans, filtration systems,fluid-conveying coils, piping or tubing, heat transfer coils, vents,louvers, dampers, valves, actuators, fluid chillers, fluid heaters, orthe like. Any of the implementations described herein can also includecontrols and logic, responsive to one or more sensors or other inputdevices or data exchange systems, for controlling the equipment for eachimplementation described herein. The term “water,” or “fluid” as usedherein, broadly describes a liquid-based heat rejection or heat transfersystem. The term “air handling unit” (“AHU”) or “fan coil unit” (“FCU”)broadly describes equipment that is designed to provide temperature andrelative humidity control to meet space conditioning and process needs.The terms “tubing”, “piping” or “fluid conduit” as used herein, broadlydescribed a passageway or means of transferring the fluid from onecomponent to another, or with a component.

Energy recovery options are shown on some implementations, but are notshown on others. One skilled in the art would understand that similarheat recovery opportunities are available from each of theimplementations described herein.

While sequences of operation and software to control each implementationare generally described, one or more implementations can includesoftware that implement algorithms and strategies that are self-tuning,self-learning, anti-equipment cycling, and are set up to make the HEDSdesign renewable energy and energy storage friendly, including softwarethat allows the HEDS system to be utilized as a Demand Response tool, ora Distributed Energy Resource, while still maintaining the relativehumidity needs of the space. These features are exclusive to the HEDSdesign.

Sample control system instrumentation inputs include one or more of thefollowing:

Air Filters Differential Pressure

Fresh air intake conditions, Return air conditions, Mixed airconditions, Supply fan plenum conditions, Preheat coil leaving airconditions, Cooling coil leaving air conditions, Cooling Recovery Coilleaving air conditions, Cooling Recovery Coil #2 leaving air conditions,Reheat coil leaving air conditions, Supply air conditions, Exhaust airconditions, Space or process load conditions, conditions for otherenergy recovery or reclaim, or heat transfer systems, including: Drybulb temperature, Wet bulb temperature, Dewpoint temperature, RelativeHumidity Setpoints, including minimum and maximum setpoints, for each ofthe above variables, Air flow rate Air flow rate setpoints, includingminimum and maximum setpoints, Water flow rates and inlet and outlettemperatures for each coil system; Water flow rates and inlet and outlettemperatures for each energy recovery or heat transfer system, Waterflow rates and inlet and outlet temperatures for each cooling andheating system.

Energy associated with all coils, energy recovery, heat transfer system,cooling and heating system and their parasitic loads (pumps, fans, etc.)

Air distribution/return/exhaust systems and space/process conditions asappropriate Fan kW, all fan types, e.g., supply, return, exhaust, labhood, make up air unit, recirculating air unit, DOAS Fan speed, all fantypes, e.g., supply, return, exhaust, lab hood, make up air unit,recirculating air unit, DOAS Pressures, pressure differentials, relativepressures, filter pressure drop, both setpoints for these variables andthe actual value of the variables.

Damper position commands, return air, fresh air, economizer VAV, CAV,MZU, FPMXB, other air distribution equipment

Damper position, actual, return air, fresh air, economizer VAV, CAV,MZU, FPMXB, other air distribution equipment

Information available from Cooling plant—chillers, heat recoverychillers, heat pumps, glycol chillers, ground source heat pumps,primary, secondary and tertiary chilled water pumps, cooling tower fans,condenser water pumps, chilled water supply temperature set point andactual values, evaporator refrigerant temperature, pressure, andapproach temperature, condenser water supply temperature set point andactual values, condenser refrigerant temperature, pressure, and approachtemperature. Refrigerant superheat, chiller KW and motor speed andfrequency, chilled water and condenser water flow rates, temperaturedifferentials, pressure differentials. Evaporator and condenserdifferential pressure minimum and maximum setpoints, compressor InletGuide Vane (IGV) position commands and actual positions, on/commandstatus, on/off status, load recycle status, alarm status, refrigerantlevel, evaporator, refrigerant level, condenser, other information thatis available via a network connection, hardwired, RF or Wi-Fi.

Instrumentation is included to measure the air pressure drop across thecooling recovery coil(s) (CRC). This air pressure drop can be used tocalculate the air flow rate of the fresh air entering the system. TheCRC is a dry coil, with no condensation occurring, so the air pressuredrop will not vary as the loads vary, only as the CFM's vary, so this isa viable and repeatable control methodology.

The air pressure drop across the CRC(s) is high enough that reasonablypriced instrumentation can be utilized to measure the differentialpressure and air flow. With a typical reheat coil, the air pressure dropat 100% air flow may only be 0.01″ to 0.03″. Pressure drop varies withthe square of air flow, so as the air flow drops off, the air pressuredrop across the coil drops off very rapidly. HEDS CRC's are larger andhave a higher air pressure drop, so the measurements will be moreaccurate and repeatable.

A HEDS-unique control algorithm is used to modulate the damper systems,fan speed and other variables as needed to maintain the desired freshair setpoint. The fresh air setpoint is varied based on time of day,type of day, day of week, occupancy, operational mode, demand controlledventilation controls and other variables.

In accordance with implementations described herein, the followingreference numbers can be referred to for specific elements of thesystems and methods:

-   -   1-0001 heating, cooling, dehumidification and air purification        system    -   1-0002 return air    -   1-0003 air handling unit    -   1-0005 fresh air    -   1-0006 fresh air damper and damper actuator    -   1-0007 return air damper and damper actuator, (N/A for 100%        fresh air systems)    -   1-0009 fresh air and return air mixing plenum, (N/A for 100%        fresh air systems)    -   1-0010 mixed air    -   1-0011 pre-heat coil (PHC) discharge air plenum    -   1-0015 cooling coil (CC or C/C) or heating coil (HC) heat        transfer system    -   1-0020 discharge air (supply air) from unit    -   1-0025 cooling coil (heating coil) discharge air plenum    -   1-0026 pre-heat coil (or pre-cool coil) heat transfer system    -   1-0027 re-heat coil (RHC) (or post-cool coil (Post-CC)) heat        transfer system    -   1-0028 humidification system    -   1-0030 cooling recovery coil (CRC or CRC #1) heat transfer        system    -   1-0031 Ultra Violet Germicidal Irradiation (UVGI), and other        chemical/biological neutralizing and filtration systems    -   1-0032 Photocatalytic Oxidation (PCO), and other        chemical/biological neutralizing and filtration systems    -   1-0033 cooling recovery coil #2 (CRC #2) heat transfer system    -   1-0035 heating source    -   1-0036 heating source    -   1-0040 cooling plant    -   1-0045 chilled fluid supply piping (e.g., conduit) (warmed fluid        supply piping (e.g., conduit) when system is used for heating)    -   1-0050 chilled fluid return piping (e.g., conduit) (warmed fluid        return piping (e.g., conduit) when system is used for heating)    -   1-0051 cooling coil (heating coil) piping (e.g., conduit)        (warmed (or cooled) fluid leaving the CC being delivered to        other components)    -   1-0055 control valve    -   1-0056 flow control valve (FCV), automatic flow control valve        (AFCV), resettable automatic flow control valve (RAFCV)    -   1-0057 cooling recovery coil bypass valve and piping (e.g.,        conduit), various valve types    -   1-0060 fan(s) or blower(s), motor(s), engines to move air    -   1-0070 heating fluid return piping (e.g., conduit) system    -   1-0071 heating fluid supply piping (e.g., conduit) system    -   1-0072 heating fluid supply piping (e.g., conduit) system to        other loads    -   1-0073 heating fluid return piping (e.g., conduit) system from        other loads    -   1-0075 heating fluid supply piping (e.g., conduit) system    -   1-0076 heating fluid return piping (e.g., conduit) system    -   1-0077 heating fluid return piping (e.g., conduit) system from        other loads    -   1-0078 heating fluid supply piping (e.g., conduit) system to        other loads    -   1-0081 three way control valve (and associated controls,        operational and optimization logic)    -   1-0082 PHC control valve (and associated controls, operational        and optimization logic)    -   1-0083 reheat coil (RHC) control valve (and associated controls,        operational and optimization logic)    -   1-0084 reheat coil (RHC) control valve (and associated controls,        operational and optimization logic)    -   1-0085 chilled fluid return piping (e.g., conduit) from other        loads (warmed fluid return piping (e.g., conduit) when system is        used for heating)    -   1-0090 chilled fluid supply piping (e.g., conduit) to other        loads (warmed fluid supply piping (e.g., conduit) when system is        used for heating)    -   1-0100 pre-filtration system and odor, chemical/biological        neutralizing and filtration systems as required    -   1-0101 post- or after-filtration system and odor,        chemical/biological neutralizing and filtration systems as        required    -   1-0111 fluid piping (e.g., conduit) leaving CRC (CRC #1)    -   1-0113 fluid piping (e.g., conduit) leaving CRC (CRC #1) and        entering CRC #2    -   1-0115 fluid piping (e.g., conduit) leaving CRC #2    -   1-0171 conditioned space or process load    -   1-0310 CRC bypass valve. Manual valve, modulating control valve,        two position control valve, differential pressure control valve,        resettable differential pressure control valve, flow control        valve, automatic flow control valve, and resettable automatic        flow control valves. Valves are of various types, configurations        and operating characteristics    -   1-0410 During cooling season, fluid leaving CC and being        supplied to other cooling systems (e.g., OSA pre-cool coils,        radiant cooling, induction units, active or passive chilled        beams, under-floor air handling units and other systems). During        heating season, where CC acts as an HC, fluid leaving HC and        being supplied to other heating systems (e.g., OSA pre-heat        coils, radiant heating, induction units, active or passive        chilled beams (which also provide heating), under-floor air        handling units and other systems).    -   1-0415 fluid being returned to the system    -   1-0420 During cooling season, fluid leaving CRC and being        supplied to other cooling systems (e.g., OSA pre-cool coils,        radiant cooling, induction units, active or passive chilled        beams, under-floor air handling units and other systems). During        heating season, where CC acts as an HC, fluid leaving CC/CRC and        being supplied to other heating systems (e.g., OSA pre-heat        coils, radiant heating, induction units, active or passive        chilled beams (which also provide heating), under-floor air        handling units and other systems).    -   1-0425 fluid being returned to the system    -   1-0430 During cooling season, fluid leaving main chilled fluid        piping (e.g., conduit) system and being supplied to other        cooling systems (e.g., OSA pre-cool coils, radiant cooling,        induction units, active or passive chilled beams, under-floor        air handling units and other systems). During heating season,        where CC acts as an HC, fluid leaving main fluid piping (e.g.,        conduit) system and being supplied to other heating systems        (e.g., OSA pre-heat coils, radiant heating, induction units,        active or passive chilled beams (which also provide heating),        under-floor air handling units and other systems).    -   1-0435 fluid being returned to the system    -   1-0440 fluid leaving the PHC and being supplied to other heating        systems (e.g., OSA pre-heat coils, radiant heating, induction        units, active or passive chilled beams (which also provide        heating), under-floor air handling units and other systems).    -   1-0445 fluid being returned to the system    -   1-0450 fluid leaving main fluid piping (e.g., conduit) system        and being supplied to other heating systems (e.g., OSA pre-heat        coils, radiant heating, induction units, active or passive        chilled beams (which also provide heating), under-floor air        handling units and other systems).    -   1-0455 fluid being returned to the system    -   1-0460 fluid leaving the RHC and being supplied to other heating        systems (e.g., OSA pre-heat coils, radiant heating, induction        units, active or passive chilled beams (which also provide        heating), under-floor air handling units and other systems).    -   1-0465 fluid being returned to the system    -   1-0470 fluid leaving main fluid piping (e.g., conduit) system        and being supplied to other heating systems (e.g., OSA pre-heat        coils, radiant heating, induction units, active or passive        chilled beams (which also provide heating), under-floor air        handling units and other systems).    -   1-0475 fluid being returned to the system    -   1-0510 energy recovery system control valve (and associated        controls, operational and optimization logic) for reheat coil        system    -   1-0520 energy recovery system control valve (and associated        controls, operational and optimization logic) for chiller low        load, non-cycling system    -   1-1010 conditioned space or process loads instrumentation,        controls, operational and optimization logic    -   1-1050 fluid bypass control valve (and associated controls,        operational and optimization logic)    -   1-1060 fluid added volume tank to improve operations, reduce        thermal and equipment cycling, and improve resiliency    -   1-1070 fluid supply piping (e.g., conduit) from ground coupled        heat sink or heat source to PHC heat transfer system    -   1-1072 control valve (and associated controls, operational and        optimization logic)    -   1-1075 fluid return piping (e.g., conduit) from PHC heat        transfer system to ground coupled heat sink or heat source    -   1-1080 fluid supply piping (e.g., conduit) from ground coupled        heat sink or heat source to RHC heat transfer system    -   1-1082 control valve (and associated controls, operational and        optimization logic)    -   1-1085 fluid return piping (e.g., conduit) from RHC heat        transfer system to ground coupled heat sink or heat source    -   1-1100 fluid expansion tank, plus associated controls, piping        (e.g., conduit) and instrumentation    -   1-1200 chilled or heated fluid pumping system for heat sink,        heat source, heating energy being recovered, heating energy        being added to the heat sink, cooling energy being recovered,        cooling energy being added to the heat sink.    -   1-1210 chilled or heated fluid pumping system for loads being        served    -   1-1300 heat pump system or cooling system utilizing a ground        coupled heat rejection system    -   1-2000 energy recovery system feeding the PHC (and associated        controls, operational and optimization logic)    -   1-2002 control valve for fluid piping (e.g., conduit) from        ground coupled heat sink or heat source to PHC heat transfer        system (and associated controls, operational and optimization        logic)    -   1-2006 energy recovery system feeding the RHC (and associated        controls, operational and optimization logic)    -   1-2008 control valve for fluid piping (e.g., conduit) from        ground coupled heat sink or heat source to RHC heat transfer        system (and associated controls, operational and optimization        logic)    -   1-2010 heating/cooling energy recovery unit #1 (HCRU #1)    -   1-2012 control valve for heating/cooling energy recovery unit #1        (HCRU #1) (and associated controls, operational and optimization        logic)    -   1-2020 heating/cooling energy recovery unit #2 (HCRU #2)    -   1-2022 control valve for heating/cooling energy recovery unit #2        (HCRU #2) (and associated controls, operational and optimization        logic)    -   1-2030 additional heating/cooling energy recovery units (HCRU        #XXXX)    -   1-2032 control valves for additional heating/cooling energy        recovery units (HCRU #XXXX) (and associated controls,        operational and optimization logic)    -   1-2040 ground coupled field for heat rejection or heat        reclamation    -   1-2042 control valve for ground coupled field for heat rejection        or heat reclamation (and associated controls, operational and        optimization logic)    -   1-2044 control valve for ground coupled field for heat rejection        or heat reclamation (and associated controls, operational and        optimization logic)    -   1-2046 control valve for ground coupled field for heat rejection        or heat reclamation (and associated controls, operational and        optimization logic)    -   1-2048 control valve for ground coupled field for heat rejection        or heat reclamation (and associated controls, operational and        optimization logic)    -   1-2050 cooling and cooling/heating system utilizing the earth        for heat rejection or heat rejection and reclamation    -   1-2060 cooling augmentation system. Allows added “cooling        energy” to be injected into the ground coupled field, for use at        a later time.    -   1-2062 control valve for cooling augmentation system and        associated controls, operational and optimization logic).    -   1-2070 heating augmentation system. Allows added “heating        energy” to be injected into the ground coupled field, for use at        a later time.    -   1-2072 control valve for heating augmentation system and        associated controls, operational and optimization logic).    -   1-3000 overall system instrumentation, controls, operational and        optimization logic.

FIG. 1 illustrates a failsafe cooling coil and cooling recovery coilsystem. The system includes one control valve per cooling coil/coolingrecovery coil system. The system failsafe cooling coil and coolingrecovery coil system employs a failsafe reheat system using a coolingrecovery coil. The cooling recovery coil (CRC) 1-0030 is in directcommunication with cooling coil (CC) 1-0015—all of the water that leavesthe CC 1-0015 goes through the CRC 1-0030—and a single control valve canbe used as one part of the capacity variation control algorithm. In someimplementations, however, no control valves are used. A manual bypassvalve and the associated piping to allow some of the chilled fluid thatleaves the CC 1-0015 to bypass the CRC 1-0030 can also be included.Alternately, some combination of fixed or adjustable, differentialpressure control valves or automatic control valves, modulating controlvalves, and manual control valves can be utilized to control the flowthrough and around the coil systems. The CRC heat transfer tubing can belocated in the same frame as the CC, or it/they can be located remotely.

In one implementation, 100% of the fluid flow that passes through thecooling coil (CC) 1-0015 passes through the cooling recovery coil (CRC)1-0030. With this configuration, even if there is some form of anequipment or control system failure, the cooled and dehumidified airgets reheated by the CRC so that it does not leave the air handling unit(AHU) with saturated or nearly saturated air conditions. In otherimplementations, rather than 100% of the CHW flow passing from the CC1-0015 into the CRC 1-0030, a desired fraction of the water can passfrom the CC 1-0015 into the CRC 1-0030, with the remainder bypassing theCRC 1-0030. The lower Relative Humidity (RH) air leaving the failsafeCRC 1-0030 reduces the potential for condensation to occur, and forrelative humidity levels to rise above the desired levels.

Control strategies can be implemented that efficiently minimize thecooling load on the compressor, while reducing compressor on/off cyclingand moisture re-evaporation off of the cooling coils and drain pans,while still keeping the building(s) positively pressurized with lowrelative humidity air as needed. This is critical to keeping highmoisture content, high vapor pressure air from migrating into thebuilding or area being treated/conditioned.

The control system is designed to vary overall capacity and energy draw,sensible, latent and energy recovery capacity by varying fan speedsetpoints and speeds, CFM setpoints and CFM's, AHU static pressuresetpoints, chilled fluid flow through the coil systems, chilled fluidpump speed setpoints and speeds, chilled fluid system differentialpressure setpoints and differential pressures, chilled fluid supplytemperature setpoints and chilled fluid supply temperatures, heatedfluid flow through the coil systems, heated fluid pump speed setpointsand speeds, heated fluid system differential pressure setpoints anddifferential pressures, heated fluid supply temperature setpoints andheated fluid supply temperatures. In accordance with someimplementations, the control methods and sequences may be performed atleast in part, by one or more controllers connected with each of theHEDS-based systems described herein, consistent with implementations ofthe current subject matter. Such control methods are described in moredetail below. The sequences shown and described herein arenon-exhaustive and non-limiting. For example, each sequence shown anddescribed may include one or more steps, each of which may not berequired. Each step of each sequence may also be performed by thecontroller (e.g., control system 300) in a different order. In someimplementations, each sequence may be combined with one or more othersequences.

For a given load, the control system can vary the dehumidification(moisture removal) capacity by changing some or all of the followingvariables and setpoints. To lower the dewpoint temperature of the airleaving the cooling coil, fan speed setpoints and speeds, CFM setpointsand CFM's, AHU static pressure setpoints, chilled fluid supplytemperature setpoints, and chilled fluid supply temperatures are reducedto lower the dewpoint temperature of the air leaving the cooling coil.Chilled fluid flow through the coil systems, chilled fluid pump speedsetpoints and speeds, chilled fluid system differential pressuresetpoints and differential pressures can be increased to lower thedewpoint temperature of the air leaving the cooling coil.

To raise the dewpoint temperature of the air leaving the cooling coil,fan speed setpoints and speeds, CFM setpoints and CFM's, AHU staticpressure setpoints, chilled fluid supply temperature setpoints andchilled fluid supply temperatures can be increased to raise the dewpointtemperature of the air leaving the cooling coil. Chilled fluid flowthrough the coil systems, chilled fluid pump speed setpoints and speeds,chilled fluid system differential pressure setpoints and differentialpressures can be reduced to raise the dewpoint temperature of the airleaving the cooling coil.

For a given load, the control system can vary the sensible capacity ofthe cooling coil by changing some or all of the following variables andsetpoints. To lower the drybulb temperature of the air leaving thecooling coil, fan speed setpoints and speeds, CFM setpoints and CFM's,AHU static pressure setpoints, chilled fluid supply temperaturesetpoints and chilled fluid supply temperatures can be reduced to lowerthe drybulb temperature of the air leaving the cooling coil. Chilledfluid flow through the coil systems, chilled fluid pump speed setpointsand speeds, chilled fluid system differential pressure setpoints anddifferential pressures can be increased to lower the drybulb temperatureof the air leaving the cooling coil.

To raise the drybulb temperature of the air leaving the cooling coil,fan speed setpoints and speeds, CFM setpoints and CFM's, AHU staticpressure setpoints, chilled fluid supply temperature setpoints andchilled fluid supply temperatures can be increased to raise the drybulbtemperature of the air leaving the cooling coil. Chilled fluid flowthrough the coil systems, chilled fluid pump speed setpoints and speeds,chilled fluid system differential pressure setpoints and differentialpressures can be reduced to raise the drybulb temperature of the airleaving the cooling coil.

For a given load, the control system can vary the sensible reheatcapacity of the cooling recovery coil by changing some or all of thefollowing variables and setpoints. To lower the drybulb temperature ofthe air leaving the cooling recovery coil, fan speed setpoints andspeeds, CFM setpoints and CFM's, AHU static pressure setpoints, chilledfluid supply temperature setpoints and chilled fluid supply temperaturescan be increased to lower the drybulb temperature of the air leaving thecooling recovery coil. Chilled fluid flow through the coil systems,chilled fluid pump speed setpoints and speeds, chilled fluid systemdifferential pressure setpoints and differential pressures can beincreased to lower the drybulb temperature of the air leaving thecooling recovery coil.

To raise the drybulb temperature of the air leaving the cooling recoverycoil, fan speed setpoints and speeds, CFM setpoints and CFM's, AHUstatic pressure setpoints, chilled fluid supply temperature setpointsand chilled fluid supply temperatures can be decreased to raise thedrybulb temperature of the air leaving the cooling recovery coil.Chilled fluid flow through the coil systems, chilled fluid pump speedsetpoints and speeds, chilled fluid system differential pressuresetpoints and differential pressures can be decreased to raise thedrybulb temperature of the air leaving the cooling recovery coil.

For a given load, the control system will vary the energy recoverycapacity of the unit by changing some or all of the following variablesand setpoints. Fan speed setpoints and speeds, CFM setpoints and CFM's,AHU static pressure setpoints, chilled fluid supply temperaturesetpoints and chilled fluid supply temperatures can be controlled tovary the energy recovery capacity of the unit. In addition, chilledfluid flow through the coil systems, chilled fluid pump speed setpointsand speeds, chilled fluid system differential pressure setpoints anddifferential pressures can be controlled to vary the energy recoverycapacity of the unit. Dry bulb and dewpoint supply air temperaturesetpoints for the unit can be controlled to vary the energy recoverycapacity of the unit.

To augment the above control system sequences, to meet the desiredsystem setpoints, these variables shall also be controlled: heated fluidflow through the coil systems, heated fluid pump speed setpoints andspeeds, heated fluid system differential pressure setpoints anddifferential pressures, heated fluid supply temperature setpoints andheated fluid supply temperatures.

Sensors monitor the indoor and outdoor conditions and use the variouscomponents of the system as needed to maintain indoor dry bulb, dewpointand RH % setpoints. There are setback setpoints programmed into thesystem, to allow wider tolerances when facilities are not occupied,while still maintaining the conditions needed to reduce/eliminate moldgrowth related to HVAC system design and operations.

Control and optimization strategies included with the system describedherein are designed to control air dry bulb temperatures, dewpointtemperatures, wet bulb temperatures and relative humidity, as well asair volumes to ensure that the desired comfort, relative humidity andtemperature conditions are met at the lowest energy point during hoursof normal activity, and that reduced air volumes, even down to zero CFM,can be used when the spaces are not occupied, or occupied in a mannerthat allows wider thermal comfort bounds to be utilized.

Other built in operational modes include a Continuous DehumidificationMode, a Batch Dehumidification Mode, a Facility Dry-out Mode, a ConstantFacility Pressurization Mode, these are briefly described later in thisapplication.

Additional options such as Ultraviolet Germicidal Irradiation (UVGI),Photocatalytic Oxidation (PCO), alternate heating or reheating sources,and after-filters are shown. A unique benefit of HEDS that is notavailable with other systems is that the lower air velocities designedinto HEDS units provides significantly longer contact time between UVGI,PCO, Chemical/biological risk mitigation systems, heating, reheating andfiltration systems, which can significantly improve their effectiveness.Humidifiers can also be installed for loads that must maintain minimumRH levels. Not all potential options have been shown.

For example, FIG. 1 illustrates a system including a cooling and/ordehumidification system. The cooling and/or dehumidification system mayinclude one or more components, such as a pre-filtration system 1-0100,one or more fans/blowers 1-0060, a pre-heat coil 1-0026, a cooling coil1-1-0015, one or more UVGI systems 1-0031, and a cooling recovery coil1-0030. In some implementations, return air 1-0002 passes through aninlet having a return air damper/actuator 1-0007 and/or fresh air 1-0005passes through another inlet having a fresh air damper/actuator 1-0006into a mixing plenum 1-0009. Mixed air 1-0010 from the mixing plenum1-0009 is blown by the one or more fans/blowers 1-0060 through thecooling and/or dehumidification system. The air may pass through thepre-heat coil 1-0026 into a pre-heat coil discharged air plenum 1-0011.The air may also pass through the cooling coil 1-0015 into a coolingcoil discharged air plenum 1-0025. The discharged air may pass throughone or more biological control systems (UVGI, etc.) 1-0031 and/or one ormore additional biological control systems (e.g., PCO, etc.) 1-0032. Theair may then pass through the cooling recovery coil 1-0030.

In some implementations, one or more fluid conduits provide a passagewayfor fluid to pass between the each of the coils (e.g., the PHC, the CC,the CRC, etc.) and/or between each of the coils and an external system,such as a cooling/chiller plant 1-0040 or heating source 1-0035, 1-0036.Each fluid conduit may include one or more sections, or one or morefluid conduits. For example, a fluid conduit may provide a fluidpassageway for fluid to flow between the heating source 1-0035 and thePHC 1-0026. As shown, the heating fluid supply 1-0075 flows from theheating source 1-0035 to an inlet of the PHC 1-0026 and through anoutlet of the PHC back to the heating source 1-0035 as heating fluidreturn 1-0070. As the fluid passes through the PHC, the temperature ofthe air passing through the PHC increases, while the temperature of thefluid passing through the PHC decreases. In some implementations, thefluid conduit includes a PHC control valve 1-0082 that controls the flowrate of the fluid flowing through the PHC and/or from the outlet of thePHC to the heating source 1-0035. The fluid conduit may also provide aheating fluid supply to other loads at 1-0078 and return the heatingfluid supply from other loads at 1-0073.

In some implementations, a fluid conduit allows fluid to pass from anoutlet of the CC 1-0015 to an inlet of the CRC 1-0030. Another fluidconduit may define a passageway between the CRC 1-0030 and the coolingplant 1-0040, and from the cooling plant 1-0040 to the CC 1-0015. In theexample shown in FIG. 1 , the fluid conduit allows a chilled fluidsupply 1-0045 to pass from the cooling plant 1-0040 to an inlet of theCC 1-0015 (and to other loads at 1-0090). As the fluid passes throughthe CC, the temperature of the fluid rises. The fluid may exit the CC1-0015 through a fluid conduit 1-0051 via the outlet and into the inletof the CRC 1-0030. As the fluid passes through the CRC 1-0030, thetemperature of the fluid decreases, as the temperature of the airpassing the CRC 1-0030 rises. The return fluid 1-0050 may exit the CRC1-0030 via an outlet through a fluid conduit 1-0111 that leads to one ormore other loads 1-0085 and/or the cooling plant 1-0040. The fluidconduit connecting the CRC 1-0030 with the cooling plant 1-0040 mayinclude one or more control valves 1-0055, as noted above, to controlthe flow rate of the fluid passing through the fluid conduit.

In some implementations, the system includes a humidification system1-0028. The humidification system 1-0028 may include a re-heat coil1-0027, one or more filters 1-0031, and a post-filtration system 1-010.In some implementations, a fluid conduit may provide a fluid passagewayfor fluid to flow between the heating source 1-0036 and the RHC 1-0027.As shown, the heating fluid supply 1-0071 flows from the heating source1-0036 to an inlet of the RHC 1-0027 and through an outlet of the RHCback to the heating source 1-0036 as heating fluid return 1-0076. As thefluid passes through the RHC, the temperature of the air passing throughthe RHC increases, while the temperature of the fluid passing throughthe RHC decreases. In some implementations, the fluid conduit includes aRHC control valve 1-0083 that controls the flow rate of the fluidflowing through the RHC and/or from the outlet of the RHC to the heatingsource 1-0036. The fluid conduit may also provide a heating fluid supplyto other loads at 1-0072 and return the heating fluid from other loadsat 1-0077. After passing through the RHC 1-0027, the air may passthrough one or more UVGI systems 1-0031, PCO systems 1-0032 and/or apost-filtration system 1-0101 to further filter the air. The air mayexit the system through an outlet at 1-0020 to a conditionedspace/process load at 1-0171.

FIG. 2 illustrates a system that is similar to the system illustrated inFIG. 1 (and includes many of the same components as illustrated in FIGS.1 and 2 ) with failsafe operation, but does not use any form of acontrol valve to modulate capacity, and accordingly, it is an ultimatein failsafe designs. Instead, the cooling and/or dehumidification systemmay include a control mechanism, such as a CRC bypass valve, a manualvalve, a modulating control valve, two position control valve, adifferential pressure control valve, a resettable differential pressurecontrol valve, a flow control valve, an automatic flow control valve,and a resettable automatic flow control valves, and the like 1-0310. Forexample, the bypass valve 1-0310 may include various valves of differenttypes, configurations and operating characteristics. The bypass valve1-0310 may divert all or a portion of the fluid passing through a firstconduit (connecting the outlet of the CC to the inlet of the CRC) to asecond conduit (connecting the outlet of the CRC with the cooling plant1-0040) to relieve pressure build-up in the first fluid conduit.Capacity control, energy draw and sensible, latent and energy recoverycapacity modulation is accomplished via changing various systemsetpoints, such as by varying fan speed setpoints and speeds, CFMsetpoints and CFM's, AHU static pressure setpoints, chilled fluid flowthrough the coil systems, chilled fluid pump speed setpoints and speeds,chilled fluid system differential pressure setpoints and differentialpressures, chilled fluid supply temperature setpoints and chilled fluidsupply temperatures, heated fluid flow through the coil systems, heatedfluid pump speed setpoints and speeds, heated fluid system differentialpressure setpoints and differential pressures, heated fluid supplytemperature setpoints and heated fluid supply temperatures. The systemcan be applied to a single unit, or a multiplicity of units that arepiped in a design that is hydraulically self-balancing, or thedifferential pressures at the individual units is relatively consistentbetween the individual units. The system can be piped for reversereturn, and designed with coil and piping pressure drops that promoterelatively even flow throughout all areas of the facility.

FIG. 3 is similar to the system illustrated in FIG. 2 with failsafeoperation (and includes many of the same or similar components, asillustrated in FIGS. 2 and 3 ), but with added functionality. Forexample, the system may include a first CRC 1-0030 (e.g., CRC1) and asecond CRC 1-0033 (e.g., CRC2). The CHW flow flows from the CC 1-0015 tothe first CRC 1-0030, with 100% of the flow (or the desired fraction ofthe flow) passing directly from the CC 1-0015 into the first CRC 1-0030.The fluid that then leaves the first CRC 1-0030 can either pass througha second CRC (CRC2) 1-0033 that may use some form of flow control tomodulate the capacity of CRC2 1-0033, or the fluid can bypass the CRC21-0033 and be fed into the return line 1-0113 (such as via a bypassvalve, for example). In this case, the failsafe operation of the CC1-0015 and the first CRC 1-0030 are augmented by CRC2 1-0033 and acontrol methodology that allows more precise temperature and RH controlin the spaces/process loads being served and greater control over theenergy consumption and demand profile of the system. If CRC2 1-0033 orthe associated control system has issues of some sort, the CC 1-0015 andCRC 1-0033 are still able to provide cooling, dehumidification andreheat.

Failsafe reheat may use cooling recovery coil (CRC) 1-0030 with secondCRC (CRC2) 1-0033 to provide more accurate temperature and RH control.The first cooling recovery coil (CRC) 1-0030 is in direct communicationwith the cooling coil (CC) 1-0015, such that all of the water thatleaves the CC 1-0015 goes through the first CRC 1-0030. A manual orautomatic bypass valve 1-0310 and the associated piping (or fluidconduits) to allow some of the chilled water that leaves the CC 1-0015to bypass the CRC 1-0030 may also be included. Alternatively, somecombination of fixed or adjustable, differential pressure control valvesor automatic control valves, modulating control valves, and manualcontrol valves can be utilized to control the flow through the coilsystems. A single control valve can be used as one part of the capacityvariation control algorithm. To provide more precise control of theleaving air conditions, the second CRC (CRC2) 1-0033 can be equippedwith a control valve 1-0081 that either sends water through the CRC21-0033 for added reheat and energy recovery capacity, or bypasses theCRC2 coil 1-0033, if less amounts of reheat and energy recovery arerequired.

In some implementations, 100% of the fluid flow that passes through thecooling coil (CC) 1-0015, passes through the cooling recovery coil (CRC)1-0030. With this configuration, even if there is some form of anequipment or control system failure, the cooled and dehumidified airleaving the CC 1-0015 gets reheated by the CRC 1-0030 so that it doesnot leave the air handling unit (AHU) with saturated or nearly saturatedair conditions. In other implementations, rather than 100% of the CHWflow passing from the CC 1-0015 into the CRC 1-0030, a desired fractionof the water can pass from the CC 1-0015 into the CRC 1-0030, with theremainder bypassing the CRC 1-0030.

The addition of CRC2 1-0033 and its capacity control/modulation systemincreases the usefulness of the invention, while still providing somelevel of failsafe operation. This lower relative Humidity (RH) airreduces the potential for condensation to occur, and for relativehumidity levels to rise above the desired levels.

Overall capacity and energy draw, sensible, latent and energy recoverycapacity can be varied by varying fan speed setpoints and speeds, CFMsetpoints and CFM's, AHU static pressure setpoints, chilled water flowthrough the coil systems, chilled water pump speed setpoints and speeds,chilled water system differential pressure setpoints and differentialpressures, chilled water supply temperature setpoints and chilled watersupply temperatures, heated fluid flow through the coil systems, heatedfluid pump speed setpoints and speeds, heated fluid system differentialpressure setpoints and differential pressures, heated fluid supplytemperature setpoints and heated fluid supply temperatures. All of thelogic sequence descriptions included for FIG. 1 are valid with respectto FIG. 3 , with the added functionality that the final dry bulbtemperature can be increased and the final RH can be decreased by use ofthe CRC2 1-0033 and its capacity control system.

FIG. 4 is similar to the system illustrated in FIG. 1 with failsafeoperation ((and includes many of the same or similar components, asillustrated in FIGS. 1 and 4 ), with at least two exceptions: 1) thatthis version is configured to condition a single unit, or a multiplicityof units that are piped in a design that is hydraulicallyself-balancing, or nearly hydraulically self-balancing, or thedifferential pressures at the individual units is relatively consistentbetween the individual units, and 2) in lieu of using a control valve inseries with the CC 1-0015 and CRC 1-0030 to assist with capacitycontrol, this variation uses a fixed or variable setpoint differentialpressure control valve 1-0310 (or other types of valves) to bypass fluidaround the CRC 1-0030 when the flow rates climb.

With this design, under low chilled water flow rates, a significantportion, up to 100%, of the CHW flow that leaves the CC 1-0015 entersthe CRC 1-0030 to provide a greater level of reheat under low loads toprovide lower RH air leaving the AHU. As the chilled water flowincreases, indicating that there is a greater load that needs to be met,there is a greater amount of CHW flow that bypasses the CRC 1-0030, sothe AHU leaving air temperature is not increased to the extent it wouldbe if all of the CHW that leaves the CC 1-0015 enters the CRC 1-0030.

Due to the chilled water pressure drop across the differential pressurecontrol valve 1-0310, even when it is 100% open to flow, there willalways be some CHW flow that is circulated through the CRC 1-0030,providing reheat and reducing the RH of the supply air even if thebypass valve is 100% open. Additionally, a manual valve 1-0310 can beinserted in that line to induce more flow through the CRC as desired orneeded.

FIG. 5 is similar to the system illustrated in FIG. 4 with failsafeoperation (and includes many of the same or similar components, asillustrated in FIGS. 4 and 5 ), but in lieu of a differential pressurecontrol valve 1-0310 in the bypass leg/fluid conduit around the CRC1-0030, there may be a fixed or adjustable automatic flow control valve(AFCV) 1-0310, among other control valves. With this configuration, agreater amount of water from the CC 1-0015 bypasses the CRC 1-0030 underlow flow rates, so less reheat is accomplished under low loads. As thechilled water flow rate increases, the AFCV limits the amount of flowthat can go around the CRC 1-0030, so a higher % of water from the CC1-0015 passes through the CRC 1-0030, providing a greater amount ofreheat energy at higher loads.

Due to the chilled water pressure drop across the fixed or adjustableautomatic flow control valve, even when it is 100% open to flow, theremay always be some CHW flow that is circulated through the CRC 1-0030,providing reheat and reducing the RH of the supply air even if the fixedor adjustable automatic flow control valve is 100% open. Additionally, amanual valve 1-0310 can be inserted in that line to induce more flowthrough the CRC as desired or needed.

FIG. 6 is similar to the system illustrated in FIG. 1 with failsafeoperation (and includes many of the same or similar components, asillustrated in FIGS. 1 and 6 ), but with added functionality. Forexample, energy recovered from the CC 1-0015 upstream or downstream fromthe CRC 1-0030 can be used in an energy efficient manner for alternateuses such as radiant cooling systems, outside air (fresh air)pre-cooling or preheating, passive or active chilled beams, inductionunits or other loads that need tempered fluid that is close to or abovethe dewpoint temperature during the dehumidification season, to avoidcondensation issues. Flow and temperature to the various loads can becontrolled by modulating control valves in the bypass legs of the piping(fluid conduit) connections, mixing valves, pumps or other means.

For example, as shown in FIG. 6 , at 1-0410, during some situations,such as during cooling season, fluid leaving the CC 1-0015 may besupplied (such as via a fluid conduit) to other cooling systems (e.g.,OSA pre-cool coils, radiant cooling, induction units, active or passivechilled beams, under-floor air handling units and other systems). Duringother situations, such as heating season, during which the CC 1-0015 mayact as a heating coil, fluid may be supplied (such as via a fluidconduit) to other heating systems (e.g., OSA pre-heat coils, radiantheating, induction units, active or passive chilled beams (which alsoprovide heating), under-floor air handling units and other systems). At1-0415, fluid from the other cooling and/or heating systems may bereturned to the cooling and dehumidification system.

Additionally, as shown in FIG. 6 , at 1-0420, in certain situations,such as during a cooling season, fluid leaving the CRC 1-0030 may besupplied to other cooling systems, (e.g., OSA pre-cool coils, radiantcooling, induction units, active or passive chilled beams, under-floorair handling units and the like). In other situations, such as duringheating season, the CC 1-0015 may act as a heating coil, thereby causingfluid leaving the outlet of the CC 1-0015 and/or the CRC 1-0030 may besupplied to other heating systems at 1-0420 (e.g., OSA pre-heat coils,radiant heating, induction units, active or passive chilled beams (whichalso provide heating), under-floor air handling units and the like). At1-0425, the fluid may return from the other cooling and/or heatingsystems to the fluid conduit between the CRC 1-0030 and the coolingplant 1-0040.

As noted above, the return fluid 1-0050 may exit the CRC 1-0030 via anoutlet through a fluid conduit 1-0111 that leads to one or more otherloads 1-0085 and/or the cooling plant 1-0040. At 1-0430, during somesituations, such as during cooling season, fluid leaving main chilledfluid piping (e.g., conduit) system may be supplied to other coolingsystems (e.g., OSA pre-cool coils, radiant cooling, induction units,active or passive chilled beams, under-floor air handling units and thelike). In other situations, such as during heating season, the CC 1-0015may act as a heating coil, thereby causing fluid leaving main fluidpiping (e.g., conduit) system to be supplied to other heating systems(e.g., OSA pre-heat coils, radiant heating, induction units, active orpassive chilled beams (which also provide heating), under-floor airhandling units and other systems).

As shown in FIG. 6 , in some implementations, fluid passing via a fluidconduit between the heating source 1-0035 and the PHC 1-0026 may alsoflow to and/or otherwise be supplied to other heating systems at 1-0440(e.g., OSA pre-heat coils, radiant heating, induction units, active orpassive chilled beams (which also provide heating), under-floor airhandling units and other systems). Fluid from the other heating systemsmay return to the fluid conduit at 1-0445. As noted above, the fluidconduit may also provide a heating fluid supply to other loads at 1-0078and return the heating fluid supply from other loads at 1-0073. Inaddition or alternatively, at 1-0450, fluid may exit the main fluidconduit and be supplied to other heating systems (e.g., OSA pre-heatcoils, radiant heating, induction units, active or passive chilled beams(which also provide heating), under-floor air handling units and othersystems). Fluid from the other heating systems may return to the fluidconduit at 1-0455 to flow to the heating source 1-0035.

In some implementations, fluid passing via a fluid conduit between theheating source 1-0036 and the RHC 1-0027 may also flow to and/orotherwise be supplied to other heating systems at 1-0460 (e.g., OSApre-heat coils, radiant heating, induction units, active or passivechilled beams (which also provide heating), under-floor air handlingunits and other systems). Fluid from the other heating systems mayreturn to the fluid conduit at 1-0465. As noted above, the fluid conduitmay also provide a heating fluid supply to other loads at 1-0072 andreturn the heating fluid supply from other loads at 1-0077. In additionor alternatively, at 1-0470, fluid may exit the main fluid conduit andbe supplied to other heating systems (e.g., OSA pre-heat coils, radiantheating, induction units, active or passive chilled beams (which alsoprovide heating), under-floor air handling units and other systems).Fluid from the other heating systems may return to the fluid conduit at1-0475 to flow to the heating source 1-0036.

The ability to use the recovered cooling and/or heating energy from thechilled fluid loop to serve these loads is unique to the designsdescribed herein. Typical HVAC system designs for humid locations mayprovide a design chilled fluid return temperature that may be 52° F. to60° F. These temperatures may typically be well below the dewpointtemperatures of the spaces being served, so if this fluid was useddirectly in the equipment or radiant cooling or heating system,condensation would occur in the equipment or spaces, or on the walls,floors and ceilings of radiantly cooled facilities, unless the watertemperature being supplied to the equipment is raised in some manner.

In some cases, completely separate cooling plants and fluid distributionsystems are installed to provide the tempered fluid that is severaldegrees above the dewpoint temperature. These separate systems can bevery energy intensive, as the cooling equipment (such as from thecooling plant 1-0040) typically operates at a 3° F. to 5° F. chilledwater system temperature differential, which can be very costly in termsof pipe, pump and variable speed drive costs and energy intensive due tothe high chilled fluid flow rates. With a HEDS implementation (such asthe systems described herein), the chilled fluid temperatures can beused directly, with a mixing valve and a pump, to provide the neededcapacities and chilled fluid temperatures.

Energy recovery is also shown to be available from the preheat coilsystem and the reheat coil system.

Other implementations can utilize similar energy recovery strategies.

FIG. 7 illustrates a system that is similar to the system illustrated inFIG. 6 with failsafe operation (and includes many of the same or similarcomponents, as illustrated in FIGS. 6 and 7 ), but does not include acontrol valve (e.g., control valve 1-0055) to modulate capacity, andaccordingly, it is an ultimate in failsafe designs. Capacity control,energy draw and sensible, latent and energy recovery capacity modulationis accomplished via changing various system setpoints, such as byvarying fan speed setpoints and speeds, CFM setpoints and CFM's, AHUstatic pressure setpoints, chilled fluid flow through the coil systems,chilled fluid pump speed setpoints and speeds, chilled fluid systemdifferential pressure setpoints and differential pressures, chilledfluid supply temperature setpoints and chilled fluid supplytemperatures, heated fluid flow through the coil systems, heated fluidpump speed setpoints and speeds, heated fluid system differentialpressure setpoints and differential pressures, heated fluid supplytemperature setpoints and heated fluid supply temperatures. The systemcan be applied to a single unit, or a multiplicity of units that arepiped in a design that is hydraulically self-balancing, or thedifferential pressures at the individual units is relatively consistentbetween the individual units. The system can be piped for reversereturn, and designed with coil and piping pressure drops that promoterelatively even flow throughout all areas of the facility.

FIG. 8 illustrates a system that is similar to the system shown in FIG.1 (and includes many of the same or similar components, as illustratedin FIGS. 1 and 8 ) with failsafe operation, except in the illustratedvariation, a fixed or variable setpoint automatic flow control valve(FCV or AFCV) 1-0056 may be used instead of a modulating control valve1-0055. AFCV's are sometimes referred to as automatic flow limitingvalves, or automatic balancing valves. The FCV (AFCV) 1-0056 is onlydepicted to be used in line with the CC 1-0015/CRC 1-0030 equipment, butit can be applied to the PHC 1-0026 and RHC 1-0027 as the designwarrants.

In some implementations consistent with the system shown in FIG. 8 ,failsafe reheat uses a CRC, such as the CRC 1-0030. The cooling recoverycoil (CRC) 1-0030 is in direct communication with cooling coil (CC)1-0015—all of the water that leaves the CC 1-0015 goes through the CRC1-0030. A fixed or variable setpoint automatic flow control valve 1-0056is used as one part of the capacity variation control. A manual bypassvalve 1-0310 and the associated piping (e.g., fluid conduit) to allowsome of the chilled fluid that leaves the CC 1-0015 to bypass the CRC1-0030 may also be included. Additionally or alternately, somecombination of fixed or adjustable, differential pressure control valvesor automatic control valves, modulating control valves, and manualcontrol valves can be utilized to control the flow through or around thecoil systems.

In one implementation, 100% of the fluid flow that passes through thecooling coil (CC) 1-0015, passes through the cooling recovery coil (CRC)1-0030. With this configuration, even if there is some form of anequipment or control system failure, the cooled and dehumidified airgets reheated by the CRC 1-0030 so that it does not leave the airhandling unit (AHU) with saturated or nearly saturated air conditions.The use of a fixed or variable setpoint automatic control valve 1-0056provides even greater failsafe operation, as the valve will never be100% closed to flow through the coils, so dehumidification and reheatwill occur even if the control system has failed.

The automatic flow control valve 1-0056 may limit the maximum flowthrough the coil systems to comply with the fixed or adjustable flowsetpoint of the valve.

The lower relative Humidity (RH) air available from the CRC(s) 1-0030reduces the potential for condensation to occur, and for relativehumidity levels to rise above the desired levels.

Overall capacity and energy draw, sensible, latent and energy recoverycapacity can be varied by varying fan speed setpoints and speeds, CFMsetpoints and CFM's, AHU static pressure setpoints, chilled fluid flowthrough the coil systems (within the limits of the flow being set by theAFCV), chilled fluid pump speed setpoints and speeds, chilled fluidsystem differential pressure setpoints and differential pressures,chilled fluid supply temperature setpoints and chilled fluid supplytemperatures.

For a given load, the control system will vary the dehumidification(moisture removal) capacity by changing some or all of the followingvariables and setpoints. To lower the dewpoint temperature of the airleaving the CC 1-0015, fan speed setpoints and speeds, CFM setpoints andCFM's, AHU static pressure setpoints, chilled fluid supply temperaturesetpoints and chilled fluid supply temperatures can be reduced to lowerthe dewpoint temperature of the air leaving the cooling coil. Chilledfluid flow through the coil systems (within the limits of the flow beingset by the AFCV), chilled fluid pump speed setpoints and speeds, chilledfluid system differential pressure setpoints and differential pressurescan be increased to lower the dewpoint temperature of the air leavingthe cooling coil.

To raise the dewpoint temperature of the air leaving the cooling coil1-0015, fan speed setpoints and speeds, CFM setpoints and CFM's, AHUstatic pressure setpoints, chilled fluid supply temperature setpointsand chilled fluid supply temperatures can be increased. Chilled fluidflow through the coil systems (within the limits of the flow being setby the AFCV 1-0056), chilled fluid pump speed setpoints and speeds,chilled fluid system differential pressure setpoints and differentialpressures can be reduced to raise the dewpoint temperature of the airleaving the CC 1-0015.

For a given load, the control system will vary the sensible capacity ofthe CC 1-0015 by changing some or all of the following variables andsetpoints. To lower the drybulb temperature of the air leaving the CC1-0015, fan speed setpoints and speeds, CFM setpoints and CFM's, AHUstatic pressure setpoints, chilled fluid supply temperature setpointsand chilled fluid supply temperatures can be reduced. Chilled fluid flowthrough the coil systems (within the limits of the flow being set by theAFCV), chilled fluid pump speed setpoints and speeds, chilled fluidsystem differential pressure setpoints and differential pressures can beincreased to lower the drybulb temperature of the air leaving the CC1-0015.

To raise the drybulb temperature of the air leaving the CC 1-0015, fanspeed setpoints and speeds, CFM setpoints and CFM's, AHU static pressuresetpoints, chilled fluid supply temperature setpoints and chilled fluidsupply temperatures can be increased. Chilled fluid flow through thecoil systems (within the limits of the flow being set by the AFCV),chilled fluid pump speed setpoints and speeds, chilled fluid systemdifferential pressure setpoints and differential pressures can bereduced to raise the drybulb temperature of the air leaving the CC1-0015.

For a given load, the control system will vary the sensible reheatcapacity of the CRC 1-0030 by changing some or all of the followingvariables and setpoints. To lower the drybulb temperature of the airleaving the CRC 1-0030, fan speed setpoints and speeds, CFM setpointsand CFM's, AHU static pressure setpoints, chilled fluid supplytemperature setpoints and chilled fluid supply temperatures can beincreased. Chilled fluid flow through the coil systems (within thelimits of the flow being set by the AFCV), chilled fluid pump speedsetpoints and speeds, chilled fluid system differential pressuresetpoints and differential pressures can be increased to lower thedrybulb temperature of the air leaving the CRC 1-0030.

To raise the drybulb temperature of the air leaving the CRC 1-0030, fanspeed setpoints and speeds, CFM setpoints and CFM's, AHU static pressuresetpoints, chilled fluid supply temperature setpoints and chilled fluidsupply temperatures can be decreased. Chilled fluid flow through thecoil systems (within the limits of the flow being set by the AFCV),chilled fluid pump speed setpoints and speeds, chilled fluid systemdifferential pressure setpoints and differential pressures can bedecreased to raise the drybulb temperature of the air leaving the CRC1-0030.

For a given load the control system will vary the energy recoverycapacity by changing some or all of the following variables andsetpoints. Fan speed setpoints and speeds, CFM setpoints and CFM's, AHUstatic pressure setpoints, chilled fluid supply temperature setpointsand chilled fluid supply temperatures can be controlled to vary theenergy recovery capacity of the unit. In addition, chilled fluid flowthrough the coil systems, chilled fluid pump speed setpoints and speeds,chilled fluid system differential pressure setpoints and differentialpressures can be controlled to vary the energy recovery capacity of theunit. Dry bulb and dewpoint supply air temperature setpoints for theunit can be controlled to vary the energy recovery capacity of the unit.

To augment the above control system sequences, to meet the desiredsystem setpoints, these variables may also be controlled: heated fluidflow through the coil systems, heated fluid pump speed setpoints andspeeds, heated fluid system differential pressure setpoints anddifferential pressures, heated fluid supply temperature setpoints andheated fluid supply temperatures.

FIG. 9 is similar to the system illustrated in FIG. 1 (and includes manyof the same or similar components, as illustrated in FIGS. 1 and 9 )with failsafe operation, but with added functionality. The CHW flowflows from the CC 1-0015 to the first CRC 1-0030, with 100% of the flow(or the desired fraction of the flow) passing directly from the CC1-0015 into the first CRC 1-0030. The water that then leaves the firstCRC 1-0030 can either pass through a second CRC 1-0033 (CRC2) that usessome form of flow control to modulate the capacity of CRC2 1-0033, or itcan bypass the CRC2 1-0033 and be fed into the return line. In thiscase, the failsafe operation of the CC 1-0015 and the first CRC 1-0030are augmented by CRC2 1-0033 and a control methodology that allows moreprecise temperature and RH control in the spaces/process loads beingserved and greater control over the energy consumption and demandprofile of the system. If CRC2 1-0033 or the associated control systemhas issues of some sort, the CC 1-0015 and CRC 1-0030 are still able toprovide cooling, dehumidification and reheat.

Failsafe reheat uses cooling recovery coil (CRC) 1-0030 with second CRC1-0033 (CRC2) to provide more accurate temperature and RH control. Thefirst cooling recovery coil (CRC) 1-0030 is in direct communication withcooling coil (CC) 1-0015, such that all of the water that leaves the CC1-0015 goes through the first CRC 1-0030. A manual bypass valve 1-0310and the associated piping to allow some of the chilled fluid that leavesthe CC 1-0015 to bypass the CRC 1-0030 may also be included.Alternately, some combination of fixed or adjustable, differentialpressure control valves or automatic control valves, modulating controlvalves, and manual control valves 1-0081, 1-0055 can be utilized tocontrol the flow through the coil systems. A control valve 1-0081,1-0055 can be used as one part of the capacity variation control. Toprovide more precise control of the leaving air conditions, the secondCRC 1-0033 (CRC2) can be equipped with a control valve 1-0081 thateither sends water through the CRC2 coil 1-0033 for added reheat andenergy recovery capacity, or bypasses the CRC2 coil 1-0033, if lessamounts of reheat and energy recovery are required.

In some implementations, 100% of the fluid flow that passes through thecooling coil (CC) 1-0015, passes through the cooling recovery coil (CRC)1-0030. With this configuration, even if there is some form of anequipment or control system failure, the cooled and dehumidified airgets reheated by the CRC 1-0030 so that it does not leave the airhandling unit (AHU) with saturated or nearly saturated air conditions.In other implementations, rather than 100% of the CHW flow passing fromthe CC 1-0015 into the CRC 1-0030, a desired fraction of the water canpass from the CC 1-0015 into the CRC 1-0030, with the remainderbypassing the CRC 1-0030.

The addition of CRC2 1-0033 and its capacity control/modulation systemincreases the usefulness of the system, while still providing some levelof failsafe operation. This lower relative Humidity (RH) air reduces thepotential for condensation to occur, and for relative humidity levels torise above the desired levels.

Overall capacity and energy draw, sensible, latent and energy recoverycapacity can be varied by varying fan speed setpoints and speeds, CFMsetpoints and CFM's, AHU static pressure setpoints, chilled fluid flowthrough the coil systems, chilled fluid pump speed setpoints and speeds,chilled fluid system differential pressure setpoints and differentialpressures, chilled fluid supply temperature setpoints and chilled fluidsupply temperatures, heated fluid flow through the coil systems, heatedfluid pump speed setpoints and speeds, heated fluid system differentialpressure setpoints and differential pressures, heated fluid supplytemperature setpoints and heated fluid supply temperatures. All of thelogic sequence descriptions included for FIG. 1 are valid with respectto FIG. 9 (and the designs shown in the other figures described herein),with the added functionality that the final dry bulb temperature can beincreased and the final RH can be decreased by use of the CRC2 1-0033and its capacity control system.

FIG. 10 is similar to the system illustrated in FIG. 1 (and includesmany of the same or similar components, as illustrated in FIGS. 1 and 10) with failsafe operation, but in lieu of using a control valve inseries with the CC 1-0015 and CRC to assist with capacity control, thisimplementation uses a fixed or variable setpoint differential pressurecontrol valve 1-0310 to bypass water around the CRC 1-0030 when the flowrates climb. With this design, under low chilled fluid flow rates, asignificant portion, up to 100%, of the CHW flow that leaves the CC1-0015 enters the CRC 1-0030 to provide a greater level of reheat underlow loads to provide warmed and lower RH air leaving the AHU. As thechilled fluid flow increases, indicating that there is a greater loadthat needs to be met, there will be a greater amount of CHW flow thatbypasses the CRC 1-0030, so the AHU leaving air temperature is notincreased to the extent it would be if all of the CHW that leaves the CC1-0015 enters the CRC 1-0030.

Due to the chilled fluid pressure drop across the differential pressurecontrol valve, there will always be some CHW flow that is circulatedthrough the CRC 1-0030, providing reheat and reducing the RH of thesupply air even if the bypass valve is 100% open. Additionally, a manualvalve 1-0310 can be inserted in that line to induce more flow throughthe CRC 1-0030 as desired or needed.

FIG. 11 is similar to the system illustrated in FIG. 10 (and includesmany of the same or similar components, as illustrated in FIGS. 10 and11 ) with failsafe operation, but in lieu of a differential pressurecontrol valve in the bypass leg around the CRC 1-0030, there is a fixedor adjustable automatic flow control valve (FCV or AFCV) 1-0310. Withthis configuration, a greater amount of water from the CC 1-0015bypasses the CRC 1-0030 under low flow rates, so less reheat isaccomplished under low loads. As the chilled fluid flow rate increases,the AFCV 1-0310 limits the amount of flow that can go around the CRC1-0030, so a higher % of water from the CC 1-0015 passes through the CRC1-0030, providing a greater amount of reheat energy at higher flowrates.

Due to the chilled fluid pressure drop across the fixed or adjustableautomatic flow control valve 1-0310, there will always be some CHW flowthat is circulated through the CRC 1-0030, providing reheat and reducingthe RH of the supply air even if the fixed or adjustable automatic flowcontrol valve is 100% open. Additionally, a manual valve can be insertedin that line to induce more flow through the CRC 1-0030 as desired orneeded.

FIG. 12 is similar to the system illustrated in FIG. 1 (and includesmany of the same or similar components, as illustrated in FIGS. 1 and 12) with failsafe operation. FIG. 12 is shown without a fan installedinside the unit, as a section that has air flow movement provided byother systems. It could be equipped with its own fans, and similarly,other implementations can be built without fans, relying on othersystems to provide air movement.

FIGS. 13-23 depict various forms of high resiliency, failsafe reheatenergy HEDS designs that can be coupled to a multitude of differentheating plant and cooling plant systems. The systems shown in FIGS.13-23 may include many of the same or similar components, as illustratedand described herein with respect to FIGS. 1-12 ). The ground sourcedheat pump options can enhance the capacity of the earth-coupled fieldsthat they are attached to. These implementations are depicted utilizingground coupled chillers and heat pump systems (e.g., see FIG. 21 ), butcan also provide similar benefits to other system configurations.

These designs can be used to replace inefficient chilled water based andDX refrigeration-based cooling dehumidification and heating/reheatingsystems that do not provide proper temperature or relative humiditycontrol or that have over-run the capacity of their heat rejection orheat reclamation systems and are not functioning properly, or havefailed. Commonly designed DX systems, can exhibit significantreliability and performance problems.

These implementations of the invention are unique designs in that theycouple all of the energy recovery benefits of the Cooling Recovery Coils(CRC's) 1-0030, 1-0033 in addition to utilizing rejected heat from thecondenser to false load the compressor to keep it from cycling on andoff frequently.

As described elsewhere, compressor cycling can cause the condensate inthe coil fin pack and drain pans to be re-evaporated when the compressoris cycled off, which causes a multitude of problems, so reducing oreliminating compressor cycling while maintaining the desired supply airdewpoint temperature, dry bulb temperature, wet bulb temperature,Relative Humidity and air volume is very important.

In some implementations, the condenser loop heat is reclaimed and usedin a preheat coil (e.g., PHC 1-0026) when the compressor is running, ascompared to other designs that may use reclaimed condenser heat as areheat energy source, never to add load to a compressor upstream of thecooling coil via a pre-heat coil, or injecting it directly into thechilled fluid return line, to keep the compressor running for relativehumidity control duties.

With existing designs, adding heat in a reheat position will typicallynot add load to a compressor fast enough, or with enough BTU's beingadded to the cooling load to keep a compressor from cycling off, sotemperature and RH control will be lost.

With existing designs, in a Dedicated Outdoor Air System (DOAS)configuration, adding reclaimed heat in the reheat position will not addload to the compressor, as there is zero air recirculation through aDOAS, so other methods must be used to keep the compressors running,such as hot gas bypass, which may be problematic and self-defeating innature as described elsewhere.

In other implementations of the current subject matter, energy recoveredfrom the condenser side or various other sources of energy can beinjected into the chilled fluid piping system return line(s) (e.g., at1-0050) without the need to install a pre-heat coil to add heat to theload upstream of the CC 1-0015 to keep the compressor operating withoutcycling on and off.

Using the energy reclaimed from the condenser side in the PHC 1-0026 andRHC 1-0027 can significantly reduce the water temperature entering thecondenser side of the cooling system. Lower water temperatures canreduce the condensing temperature and refrigerant pressure inside thecooling equipment. Reduced condenser side refrigerant pressures improveenergy efficiency and also increase the cooling capacity of theequipment, within limits.

FIG. 13 depicts one form of a HEDS implementation that is similar toFIG. 1 with failsafe operation (and includes many of the same or similarcomponents, as illustrated in FIGS. 1 and 13 , and otherwise describedherein), but does not use any form of a control valve to modulatecapacity, and accordingly, it is an ultimate in failsafe designs.Capacity control, energy draw and sensible, latent and energy recoverycapacity modulation is accomplished via changing various systemsetpoints, such as by varying fan speed setpoints and speeds, CFMsetpoints and CFM's, AHU static pressure setpoints, chilled fluid flowthrough the coil systems, chilled fluid pump speed setpoints and speeds,chilled fluid system differential pressure setpoints and differentialpressures, chilled fluid supply temperature setpoints and chilled fluidsupply temperatures, heated fluid flow through the coil systems, heatedfluid pump speed setpoints and speeds, heated fluid system differentialpressure setpoints and differential pressures, heated fluid supplytemperature setpoints and heated fluid supply temperatures. The systemcan be applied to a single unit, or a multiplicity of units that arepiped in a design that is hydraulically self-balancing, or thedifferential pressures at the individual units is relatively consistentbetween the individual units. The system can be piped for reversereturn, and designed with coil and piping pressure drops that promoterelatively even flow throughout all areas of the facility. The systemcan be built as a package, and can be combined with the heat pump systemshown in FIGS. 21-23 , which uses a combination of ground-coupled heatrejection/heat reclamation and various levels of energy recovery andenergy storage and energy storage augmentation for energy optimization.

This implementation is configured to condition a single unit, or amultiplicity of units that are piped in a design that is hydraulicallyself-balancing, or the differential pressures at the individual units isrelatively consistent between the individual units.

The system is resilient due to its design, in that it will alwaysprovide some form of recovered energy reheat for relative humiditycontrol and is capable of effectively operating at lower load conditionsdown to 0% cooling load, which still require dehumidification, e.g.,when the conditions are cold and “clammy.”

In contrast with these implementations of the current subject matter,typical systems cannot operate effectively, efficiently, reliably orwith stability at these low loads. With the system designs describedherein, the heat rejected by the cooling/dehumidification process can berejected at both the PHC 1-0026 to false load the compressor in anenergy efficient manner to keep it operational and keep the compressorfrom cycling on and off, as well as providing additional reheat energyvia the reheat coil over and above that which may be available from theCRC 1-0030, or the CRC 1-0030 and CRC2 1-0033 as appropriate, to ensurethat the RH of the air leaving the unit is sufficiently low to preventthe growth of mold. The RHC 1-0027 would typically not be used for RHcontrol, as there would typically be enough low quality heat energycontained in the chilled fluid leaving the CC 1-0015 and entering theCRC 1-0030 (and or CRC2 1-0033) to adequately control the RH of thesupply air and the conditioned spaces. With some operational modes, allof the energy that can be reclaimed, up to the full system capacity,would be used by incorporating the pre heat coil and reheat coils, tokeep facilities dry, or to dry them out.

It has been proven that on/off compressor cycling, whenever thecompressor cycles off, can create situations where condensation on thecoils and in the drain pans can become re-evaporated into the airstream,ductwork and occupied spaces, increasing the potential for mold growth,so there is a need to keep compressors operational and providingconsistent dehumidification by accurately maintaining CC 1-0015 leavingair temperatures. Additionally, chilled water based Constant Air Volume(CAV) systems must be continuously driven to supply the minimum designair temperature and then have that sub-cooled air reheated to provideproper RH control. Refer to Trane Engineers Newsletter Volume 33-2,FIGS. 2, 3, 4 and 5 , and FIG. 1-1 excerpted from DOE/NETL Project No.DE-FC26-01NT41253 that depict these situations.

The design of the ground-coupled heat rejection/heat recovery system issuch that heating energy that is rejected into the ground during thecooling mode or season can be recaptured and used for heating thefacility when heat is required. With these implementations, similarpre-heat, anti-compressor cycling and reheat/energy recoveryfunctionality can be achieved by utilizing refrigerant to air heatexchangers, or refrigerant to water to air heat exchangers for systemsthat utilize air cooled or evaporatively cooled heat rejection systems,or by using water to air heat exchangers for water cooled orfluid-cooler-cooled heat rejection systems.

During the heating season, typical heating systems utilize very smallheat transfer coils and are designed to utilize 180° F.+hot water supplytemperatures, or even steam heating coils. Electric strip heaters canoperate at several hundred degrees F.

A unique aspect of the systems described herein is that the size anddesign of the HEDS unit heat transfer systems allows very low qualityheat energy to be used to provide reheat energy for RH control and tokeep facilities warm.

For example, typical design temperatures for heating hot water is 180 F+which is a very inefficient operating point for heating equipment. Thesetemperatures cannot typically be provided by a heat pump system withouta booster heating system, or a dedicated heating boiler plant, at verypoor system efficiencies.

With HEDS implementations, heating water that is easily and efficientlyavailable at 85° F. from a heat pump system in the heating mode, or froma condensing boiler at 95%+ efficiency can provide supply airtemperatures of between 80° F. and 84° F. to heat the facilities,depending on the load and air volumes. At the start of the heatingsystem, it is very likely that the heat quality stored in the earth canbe used directly as the heat source for the loads, without running thecompressor. These implementations are unique and are specificallydesigned to allow this energy saving feature to occur. Similarly,typical chiller systems are designed to reject heat from the coolingprocess at a temperature of approximately 95° F. for the water leavingthe chiller. Fluid temperatures of approximately 95° F. can provideheating air temperatures of between 90° F. and 94° F. to heat thefacilities, depending on the load and air volumes. Air cooled andevaporatively cooled equipment can provide heat at similar qualitylevels. Removing heat from the condenser side of the equipment and usingit for pre-heating duties, reheating duties, or heating duties canreduce the refrigerant pressures in the condenser. Lower compressorrefrigerant lift (the difference between the refrigerant pressure in theevaporator and the refrigerant pressure in the condenser) reduces thepower required for cooling or heating, or increases the compressorcooling or heating capacity, or both, so the ability to providerelatively low heating hot water temperatures from the condenser side ofthe heat pump equipment to meet heating needs saves energy, and alsoreduces piping losses through the insulation systems, since the heatinghot water temperatures that can be effectively used with theseinventions can be 100° F. cooler than the typically designed heatingsystems equipment. HEDS, as described herein, allows system efficienciesand life cycle costs that cannot be matched by any other form of chilledfluid system based temperature and relative humidity control system.

Control strategies can be implemented that efficiently minimize thecooling load on the compressor, while reducing compressor on/off cyclingand moisture re-evaporation off of the cooling coils and drain pans,while still keeping the building(s) positively pressurized with lowrelative humidity air as needed. This may be critical to keeping highmoisture content, high vapor pressure air from migrating into thebuilding or area being treated/conditioned.

Other control strategies can be implemented that utilize the recoveredenergy based pre-heat coils and reheat coils and lowering the chilledfluid leaving temperature setpoint to significantly load the compressorto maximize the moisture removal effect on the air, while addingsignificant amounts of reheat energy to lower the RH of the air in theunit, ductwork and facility. This can be used to dry the equipment,ductwork and facility out.

Sensors monitor the indoor and outdoor conditions and use the variouscomponents of the system as needed to maintain indoor dry bulb, dewpointand RH % setpoints. There are setback setpoints programmed into thesystem, to allow wider tolerances when facilities are not occupied,while still maintaining the conditions needed to reduce/eliminate moldgrowth related to HVAC system design and operations.

Another unique aspect of these implementations of the current subjectmatter described herein is the use of energy reclaimed from thecondenser side of the system to add load to the compressor via thePre-Heat Coil (PHC) 1-0026 or chilled water loop to allow the compressorto stay online and providing stable, accurate and repeatable relativehumidity control during low load conditions, all the way down to 0%cooling load.

This is being done instead of the typically problematic methods to addload to the compressor of injecting hot, high pressure, condenser siderefrigerant gas into the evaporator or the refrigerant return line tothe compressor. The older methods are typically referred to as “Hot GasBypass”, or HGBP. The typical HGBP methods can cause operational andstability issues as the hot gas bypass valves are staged open and closedand then controlled.

In one HGBP strategy, hot refrigerant gas is injected into the suctionline of the compressor to false load the compressor. This can alsoincrease the superheat of the refrigerant gas that enters thecompressor(s) causing thermal stress and premature equipment failures.

In many cases, the HGBP system is only enabled below 20% to 40% loads,but that does not help with the compressor cycling problem between thatrange and 100% load, where operation of these systems becomes morestable and repeatable. Even if the older systems were set up to run HGBPto keep the compressor loaded to 100%, the method of injecting the hotgas into the system to false-load the compressor may preclude theability of the system to provide proper RH control, as the airtemperature leaving the cooling coil may be increased well above thedesired dewpoint temperature, causing RH control to fail.

Hot gas lines leading up to the HGBP solenoids and control valves mayalso be filled with condensed refrigerant in liquid form, so that whenthe hot gas lines are enabled and the HGBP solenoid and control valvesare opened up, the evaporator or the compressor suction line can receivea slug of liquid refrigerant. Depending on the conditions, this slug ofliquid refrigerant may not be completely evaporated and may make it backto the compressor. For many compressor types, liquid, even in the formof very fine droplets or a fine mist, entering the compressor can causeirreparable damage, creating the need for either a complete compressorrebuild, or a compressor replacement.

While the use of HGBP to add load to the compressor with existingdesigns will keep it running under light loads, there is nocorresponding improvement in efficiency due to head pressure relief,e.g., reduced refrigerant pressures in the condenser as is the case withthe various implementations of this invention. Removing heat from theheat rejection system via the preheat coil and/or reheat coil to falseload the compressor reduces the refrigerant pressure in the condenser,improving energy efficiency and capacity.

Additionally, if HGBP it is installed in another typical manner,injecting the hot refrigerant gas into or upstream of the refrigerantdistributor, or directly into the evaporator section, temperature and RHcontrol can become very erratic, and the supply air temperatures can beaffected to the degree that relative humidity control can be lost.

Eliminating loss of temperature and RH control are the main drivers forkeeping the compressor running at light loads, rather than cycling it onand off as the loads are met and then overcooled.

For chillers with flooded evaporators, the hot refrigerant gas can beintroduced at the bottom of the evaporator section, which is mostlyfilled with cold, low pressure liquid refrigerant. If hot gas isinjected directly into the evaporator, significant and violentrefrigerant boiling can occur that can send liquid refrigerant dropletsor mist back into the compressor suction line, creating problems. Theexisting technologies can become self-defeating, in their inability toprovide stable temperature and RH control, their excessive energy use,and their potential to cause equipment damage.

With existing designs, even with the use of HGBP to control compressorloading, temperature and RH control can be very poor. Using a variableair flow system design, such as the design utilized by HEDS in someimplementations, can improve both temperature and RH control.

The unique use of HEDS as described herein and the energy recovery basedpreheat coil or chilled fluid loop line connections to create loads inthe proposed inventions is significantly more stable, as the heatingcapacity can be modulated to maintain the compressor at a desired levelof capacity, rather than being staged on and off, as is the case withmost HGBP based systems. There may be no chance for liquid refrigerantslugs to make it back into the compressor suction lines, or thecompressor, and the supply air temperatures are stable and maintained atsetpoint down to 0% cooling loads.

The implementations of the current subject matter described herein areunique in that by using heat rejected from the compressor system tofalse load the compressor, the condenser cooling liquid temperature canbe reduced in a meaningful manner. This allows the head pressure(condenser side refrigerant pressure) to be reduced with essentiallyzero energy expended, improving compressor and system capacity andefficiency.

In some implementations, a system in accordance with the disclosureherein includes control algorithms and methods for capacity control,head pressure control, pre-heat water volumes and temperatures, chilledwater volumes and temperatures, cooling water volumes and temperatures,reheat water volumes and temperatures, pressures, and flow rates, reheatenergy recovery and the control algorithms look at Relative Humidity,chiller and compressor loads, drybulb temperatures, dewpointtemperatures, building pressure, Grid loading, renewables and batterystorage availability, and other input variables, etc. The controlmethods and sequences may be performed at least in part, by one or morecontrollers connected with each of the HEDS-based systems describedherein, consistent with implementations of the current subject matter.Such control methods are described in more detail herein. The sequencesshown and described herein are non-exhaustive and non-limiting. Forexample, each sequence shown and described may include one or moresteps, each of which may not be required. Each step of each sequence mayalso be performed by the controller (e.g., control system 300) in adifferent order. In some implementations, each sequence may be combinedwith one or more other sequences.

Similar HEDS-based pre-heat, compressor-load-additive, anti-compressorcycling logic and functionality can be achieved by utilizing refrigerantto air heat exchangers, or refrigerant to water heat exchangers, orrefrigerant to water to air heat exchangers for air cooled orevaporatively cooled systems, or by utilizing liquid to air heatexchangers for water cooled, or fluid-cooler-cooled cooling systems. Theterm “water,” or “fluid” as used herein, broadly describes aliquid-based heat rejection or heat transfer system.

Control and optimization strategies included with the systems describedherein are designed to control air dry bulb temperatures, dewpointtemperatures, wet bulb temperatures and relative humidity, as well asair volumes to ensure that the desired comfort, relative humidity andtemperature conditions are met at the lowest energy point during hoursof normal activity, and that reduced air volumes, even down to zero CFM,can be used when the spaces are not occupied, or occupied in a mannerthat allows wider thermal comfort bounds to be utilized.

Other built in operational modes include a Continuous DehumidificationMode, a Batch Dehumidification Mode, a Facility Dry-out Mode, a ConstantFacility Pressurization Mode, these are briefly described next.

The Continuous Dehumidification Mode can be used, such as when afacility is unoccupied or occupied in a setback mode and the internalrelative humidity and moisture content are above the desired setpoints.In this mode, cooling capacity is sent to the cooling coil (CC) (e.g.,CC 1-0015) to reduce the dewpoint temperature of the air leaving the CC.100% of the fluid leaving the CC 1-0015 is routed to the CRC 1-0030, orthe CRC 1-0030 and the CRC2 1-0033, as may be the case.

The intent is to provide low dewpoint air at the warmest drybulbtemperature possible using reclaimed energy to reduce the loads on thecompressor and reduce cooling loads on the facility due to temperaturedifferences between the ambient conditions and the conditions within thefacility.

If the loads on the compressor are too low, reclaimed energy heatingload from the condenser side of the system (or other systems) will beadded to the least extent possible to keep the compressor from cyclingoff. The amount of heat sent to the preheat coil(s) or chilled fluidreturn line is controlled to minimally load the compressor to keep itoperational. Variables will be monitored as needed to ensure that theleast amount of energy is wasted to perform this function.

The ability to add heat to false load the compressor using the preheatcoil strategy also provides significant reheat energy into the CRC1-0030, which then reduces the loads on the compressor, improving systemefficiency. Using reclaimed condenser loop heat injected directly intothe chilled water return line will also false load the compressor to theextent required to keep the compressor loaded.

If it is desired to raise the temperature inside the building,additional reclaimed energy can be injected into the system via thepreheat coil (e.g., PHC 1-0026), the reheat coil (e.g., RHC 1-0027) orthe return fluid line (e.g., 1-0050) to the cooling plant (e.g.,1-0040). Up to 100% of the rejected heat can be used to increase thespace temperature and lower the space RH. If greater heat quantities arerequired, load will need to be added to the compressor system via thepreheat coil or the chilled fluid return line, and excess heat energyfrom the process can be used to heat the air up via the CRC(s) 1-0030,1-0033 and the reheat coil 1-0027.

If it is desired to provide lower dewpoint air, the amount of heat beingsent to the preheat coil 1-0026 can be modulated and the supply airtemperature setpoint can be dropped, and those will false load thecompressor to the desired level. The benefit is that the air will belower dewpoint air, and lower overall RH air.

If the unit is a recirculating air unit, using condenser loop heatrejected solely into the reheat coil will false load the compressor overtime, not instantaneously—as warmed up air is sent to the space, theadded loads will eventually return back to the compressor and the supplyair temperatures will continue to increase and the supply air RH willcontinue to decrease over time until the unit is at or near fullcapacity.

If the unit is a non-HEDS 100% fresh air, DOAS-style unit, the abilityto false load the compressor using solely the condenser loop heatrejected into the reheat coil 1-0027 does not exist, as heat injecteddownstream from the CC 1-0015 will not false load the compressor. Whenfresh air loads are high, existing systems can provide low dewpoint, lowRH, warm air to dry the facility out. This is due to existing designsnot being able to add load to the compressor in an effective manner.With existing designs, under low load, this functionality does notexist.

With a HEDS based system such as the implementations of the currentsubject matter described herein, the supply air temperature setpoint canbe dropped, the chilled fluid setpoint can be dropped, and the chilledfluid pump speed and the AHU fan speed (if appropriate) can be increasedand that will false load the compressor. If there is a PHC upstream fromthe CC, or a connection into the CHW loop return line, the compressorcan be fully loaded. The added benefit is that the air will be lowerdewpoint air, and perhaps lower overall RH air.

Depending on the system configuration, a combination of fresh air forpressure control and recirculated air for temperature and RH control,can be utilized, all the way up to 100% fresh air intake as needed forpressure control, with the exhaust systems shut down, or modulated asneeded.

The Batch Dehumidification Mode may be similar to the ContinuousDehumidification Mode, but the system may not run continuously, at thesystem runs as a Batch process.

As with the other modes, instrumentation is utilized that monitorsindoor and outdoor dry bulb, dewpoint and wet bulb temperature, andrelative humidity conditions, including wind speeds and pressuredifferentials between the indoor and outdoor conditions, and weatherforecasts. Control methods determine how often the system will run inthis mode and how long the off cycles will be. The Constant FacilityPressurization Mode is a variation on the Continuous DehumidificationMode, but facility pressurization takes more control. The main HVACsystem equipment may be operational, but it may just be a HEDS DOAS unitthat is operational, bringing in the correct levels of fresh air tomaintain the building in a slightly positive air pressure relationshipto the outdoors. Typical operation may be to provide fresh airquantities of 10% to 25% of the design circulated airflow into thebuilding, with minimal use of the exhaust systems.

The systems and methods described herein are provided to have positiveair pressure to reduce vapor migration into a building. While manybuildings are well-built, many more have “leaky” facades that allowvapor migration into the building which can then lead to a myriad ofproblems. This can be as simple as a building with operable windows thatdo not seal well when closed to facilities that were not constructedwell, or not designed for air-tightness.

A Vapor Battery™ mode is designed to allow the HEDS design describedherein to operate as a Distributed Energy Resource (DER) to increase anddecrease the loads on the electrical grid as directed by any number ofowner or utility signals or commands, be they fully automated or manualin nature.

When the HEDS implementations described herein may increase demand onthe grid, the variables can be controlled to increase the electricaldemand up to 100% of the capacity of the system. Such configurations mayprevent significant load and capacity imbalances that can occur on thegrid, helping to promote grid health.

Additionally, the HEDS user may actually be paid to increase the demandon the grid, so this can be a financially lucrative operational mode, ifnot an energy efficient one. Conversely, the load on the grid can bediminished by allowing the dry bulb and dewpoint temperatures and the RHsetpoints to be relaxed. Temperature and RH limits can be exceeded forseveral hours without fear of biological growth. For extended outages orgrid problems, the Vapor Battery and Batch Dehumidification Modes wouldbe operated in sync with one another, and wider thermal setback rangescould be incorporated.

Facility Dry Out Mode uses condenser loop heat reclaim to false load thecompressor via the preheat and reheat coils and airside system setpointchanges,

The Facility Dry-Out Mode can be used in some situations, such as when afacility is occupied or unoccupied and the internal relative humidityand moisture content are above the desired setpoints. In this mode, theamount of heat sent to the preheat coil(s) or chilled fluid return lineis controlled to fully load the compressor, or load the compressor asneeded to provide a high enough volume of low RH, low dewpoint, warm tohot supply air into the facility. The ability to add heat to false loadthe compressor using the preheat coil strategy also provides significantreheat energy into the CRC 1-0030, which then reduces the loads on thecompressor, improving system efficiency. Using reclaimed condenser loopheat injected directly into the chilled water return line will falseload the compressor and allow significant heat to be injected into theairstream downstream from the CC 1-0015 and CRC 1-0030, which will raisethe unit supply air temperature and lower the unit supply air RH. If itis desired to provide lower dewpoint air and the compressor is fullyloaded, the amount of heat being sent to the preheat coil can be reducedand the supply air temperature setpoint can be dropped, and that willfalse load the compressor to the desired level. The added benefit isthat the air may be lower dewpoint air, and may be lower overall RH air.

If the unit is a recirculating air unit, using condenser loop heatrejected solely into the reheat coil will false load the compressor overtime, not instantaneously—as warmed up air is sent to the space, theadded loads will return back to the compressor and the supply airtemperatures will continue to increase and the supply air RH willcontinue to decrease over time until the unit is at or near fullcapacity.

If the unit is a non-HEDS 100% fresh air, DOAS-style unit, the abilityto false load the compressor using solely the condenser loop heatrejected into the reheat coil does not exist, as heat injecteddownstream from the CC 1-0015 will not false load the compressor. Whenfresh air loads are high, existing systems can provide low dewpoint, lowRH, warm air to dry the facility out, albeit in a slightly slower mannerthan the other implementations. This is due to existing designs notbeing able to add load to the compressor in an effective manner. Withexisting designs, under low load, this functionality does not exist.

With a HEDS based system such as implementations of the current subjectmatter described herein, the supply air temperature setpoint can bedropped, the chilled fluid setpoint can be dropped, and the chilledfluid pump speed and the AHU fan speed (if appropriate) can be increasedand that will false load the compressor. The added benefit is that theair will be lower dewpoint air, and perhaps lower overall RH air.

None of these unique operating strategies can be effectively,efficiently and reliably used without some form of energy recovery fromthe chilled water loop as described by the various implementations ofthe current subject matter described herein.

FIG. 14 depicts a system that is similar to FIG. 13 with failsafeoperation (and includes many of the same or similar components, asillustrated in FIGS. 13 and 14 , and otherwise described herein), but isdepicted providing HVAC services for multiple AHUs vs. a single AHU asdescribed and shown in FIG. 13 .

FIG. 15 depicts a system that is similar to FIG. 13 (and includes manyof the same or similar components, as illustrated in FIGS. 13 and 15 ,and otherwise described herein), with failsafe operation, but with addedfunctionality available with the addition of CRC2 1-0033 and theassociated equipment, controls and logic, that can be controlled in amanner that provides more accurate temperature and relative humiditycontrol for the supply air leaving the unit and the space(s) beingconditioned. This implementation is described in more detail in thediscussion for FIG. 19 below.

FIG. 16 depicts a system that is similar to FIG. 15 with failsafeoperation (and includes many of the same or similar components, asillustrated in FIGS. 15 and 16 , and otherwise described herein), but isdepicted providing HVAC services for multiple AHUs vs. a single AHU asshown in FIG. 15 and elsewhere. CRC2 1-0033 functionality is describedin further detail below with respect to FIG. 19 .

FIG. 17 is similar to the system illustrated in FIG. 13 with failsafeoperation (and includes many of the same or similar components, asillustrated in FIGS. 13 and 17 , and otherwise described herein), butdoes not use any form of a control valve to modulate capacity, andaccordingly, it is an ultimate in failsafe designs. Capacity control,energy draw and sensible, latent and energy recovery capacity modulationis accomplished via changing various system setpoints, such as byvarying fan speed setpoints and speeds, CFM setpoints and CFM's, AHUstatic pressure setpoints, chilled fluid flow through the coil systems,chilled fluid pump speed setpoints and speeds, chilled fluid systemdifferential pressure setpoints and differential pressures, chilledfluid supply temperature setpoints and chilled fluid supplytemperatures, heated fluid flow through the coil systems, heated fluidpump speed setpoints and speeds, heated fluid system differentialpressure setpoints and differential pressures, heated fluid supplytemperature setpoints and heated fluid supply temperatures. The systemcan be applied to a single unit, or a multiplicity of units that arepiped in a design that is hydraulically self-balancing, or thedifferential pressures at the individual units is relatively consistentbetween the individual units. The system can be piped for reversereturn, and designed with coil and piping pressure drops that promoterelatively even flow throughout all areas of the facility.

The system shown in FIG. 17 utilizes heating energy reclaimed from thecondenser system directly injected into the chilled water return line1-0050 as it returns to the cooling plant 1-0040 to false load thecompressor. This allows stable and efficient unloading down to 0% load,which is unavailable with other technologies. The direct injection ofreclaimed heat to false load the compressor is utilized in lieu of apreheat coil, for locations that do not need a pre-heat coil.

FIG. 18 is similar to the system illustrated in FIG. 17 with failsafeoperation (and includes many of the same or similar components, asillustrated in FIGS. 17 and 18 , and otherwise described herein), but isdepicted providing HVAC services for multiple AHUs vs. a single AHU asshown in FIG. 17 . In addition, the system illustrated in FIG. 18 mayinclude one or more control valves 1-0055, energy recovery systemcontrol valves 1-0520 (and associated controls, operational andoptimization logic) for chiller low load, non-cycling systems, energyrecovery system control valves 1-0510 (and associated controls,operational and optimization logic) for reheat coil systems, and thelike for modulating flow capacity.

FIG. 19 is similar to the system illustrated in FIG. 17 with failsafeoperation (and includes many of the same or similar components, asillustrated in FIGS. 17 and 19 , and otherwise described herein), butwith added functionality. The CHW flow flows via a fluid conduit fromthe CC 1-0015 to the first CRC 1-0030, with 100% of the flow (or thedesired fraction of the flow) passing directly from the CC 1-0015 intothe first CRC 1-0030. The water that then leaves the first CRC 1-0030can either pass through a second CRC 1-0033 (CRC2) that uses some formof flow control (e.g., 1-0081) to modulate the capacity of CRC2 1-0033,or it can bypass the CRC2 1-0033 and be fed into the return line. Inthis case, the failsafe operation of the CC 1-0015 and the first CRC1-0030 are augmented by CRC2 1-0033 and a control methodology thatallows more precise temperature and RH control in the spaces/processloads being served and greater control over the energy consumption anddemand profile of the system. If CRC2 1-0033 or the associated controlsystem has issues of some sort, the CC 1-0015 and CRC 1-0030 are stillable to provide cooling, dehumidification and reheat.

Failsafe reheat uses cooling recovery coil (CRC) 1-0030 with second CRC1-0033 (CRC2) to provide more accurate temperature and RH control. Thefirst cooling recovery coil (CRC) 1-0030 is in direct communication withcooling coil (CC) 1-0015, such that all of the fluid that leaves the CC1-0015 goes through the first CRC 1-0030. A manual bypass valve and theassociated piping to allow some of the chilled water that leaves the CC1-0015 to bypass the CRC 1-0030 may also be included. Alternately, somecombination of fixed or adjustable, differential pressure control valvesor automatic control valves, modulating control valves, and manualcontrol valves (e.g., valve 1-0081, 1-0310, 1-0520) can be utilized tocontrol the flow through the coil systems. A single control valve can beused as one part of the capacity variation control. To provide moreprecise control of the leaving air conditions, the second CRC 1-0033(CRC2) can be equipped with a control valve 1-0081 that either sendsfluid through the CRC2 1-0033 coil for added reheat and energy recoverycapacity, or bypasses the CRC2 1-0033 coil, if less amounts of reheatand energy recovery are required.

In some implementations, 100% of the fluid flow that passes through thecooling coil (CC) 1-0015, passes through the cooling recovery coil (CRC)1-0030. With this configuration, even if there is some form of anequipment or control system failure, the cooled and dehumidified air isreheated by the CRC 1-0030 so that it does not leave the air handlingunit (AHU) with saturated or nearly saturated air conditions. In otherimplementations, rather than 100% of the CHW flow passing from the CC1-0015 into the CRC 1-0030, a desired fraction of the fluid can passfrom the CC 1-0015 into the CRC 1-0030, with the remainder bypassing theCRC 1-0030.

The addition of CRC2 1-0033 and its capacity control/modulation systemincreases the usefulness of the invention, while still providing somelevel of failsafe operation. This lower relative Humidity (RH) airavailable from the use of CRC2 1-0033 reduces the potential forcondensation to occur, and for relative humidity levels to rise abovethe desired levels.

Overall capacity and energy draw, sensible, latent and energy recoverycapacity can be varied by varying fan speed setpoints and speeds, CFMsetpoints and CFM's, AHU static pressure setpoints, chilled water flowthrough the coil systems, chilled water pump speed setpoints and speeds,chilled water system differential pressure setpoints and differentialpressures, chilled water supply temperature setpoints and chilled watersupply temperatures. All of the logic sequence descriptions included forthe various implementations described herein are applicable to theimplementations described with respect to FIG. 19 , with the addedfunctionality that the final dry bulb temperature can be increased andthe final RH can be decreased by use of the CRC2 1-0033 and its capacitycontrol system.

FIG. 20 is similar to the system illustrated in FIG. 18 with failsafeoperation (and includes many of the same or similar components, asillustrated in FIGS. 18 and 20 , and otherwise described herein), butwith added functionality available with the addition of CRC2 1-0033 andthe associated equipment, controls and logic, as described above withreference to at least FIG. 15 . CRC2 1-0033 functionality is describedin further detail above with respect to FIG. 19 .

HEDS Based Ground Source Heat Pump Earth Field Capacity EnhancementSystem

FIGS. 21-23 depict a cooling/heating plant based on a modified heat pumpdesign (or standard chiller-based design) that is built to providerelative humidity control, even down to 0% cooling loads, whileenhancing the capacity of the earth-coupled field that it is attachedto.

Many existing earth sourced systems are no longer effective, as theirheat rejection/absorption fields are undersized for the loads beingserved. Heating dominated HVAC or process load systems tend to overcoolthe earth source over time, and cooling dominated HVAC or process loadsystems tend to overheat the earth source over time. Implementations ofthe current subject matter can improve the performance of those systems.

In addition to increasing the effective capacity of the earth to storeand reclaim energy, the systems described herein may solve many commonproblems associated with HVAC heating, cooling, dehumidification, reheatsystems. Performance, ability to control relative humidity and moldgrowth, resiliency, reliability, robustness and energy consumption areaddressed. The ability to be controlled to influence the electrical loadon the grid by ramping up and ramping down, and to respond as aDistributed Energy Resource (DER), and be included in Demand Response(DR) programs, while still maintaining relative humidity control in theconditioned spaces, while consuming zero site water for heat rejections,is unique to implementations of the current subject matter describedherein.

Heating and cooling load-side Thermal Energy Storage (TES) allowssmaller systems to be utilized, or undersized systems to begin to servetheir loads, or compressor systems to be utilized when renewable energyor less expensive energy is available and then shut down to utilize thestored thermal energy when renewable capacity is reduced, or whenutility costs are higher. The load side design is unique, in that theTES tank can be utilized for heat energy storage as well as coolingenergy storage with a very simple valve system and control strategy.While one implementation is shown, other implementations that mayutilize different pumping and valve arrangements can be utilized aswell. The load side TES system can be charged with heating or coolingenergy via the compressor system, or when weather conditions arefavorable, the HCRU equipment and the cooling and heating augmentationsystems connected via the ground loop piping system may be able toprovide capacity in an efficient manner. Stored energy that may bedirectly available from the earth field (without operating thecompressors) can also be used to charge the load side TES systems.

These implementations significantly decrease the cooling anddehumidification loads that need to have heat rejected into the earth,and allow much colder heating water temperatures to be used to keepfacilities warm or process loads met. Thus the effective capacity of theearth to work with the HVAC systems is greatly enhanced. The combinedsystems can greatly increase the applicability, effectiveness,efficiency and site availability for ground-sourced, or earth-sourcedheat pump systems. (sometimes referred to as geothermal heat pumps,geo-exchange heat pumps, or earth-coupled heat pump systems).

The equipment sizing, design and control strategies allow the use of thecooling energy stored in the earth over the winter to be used directlyto provide cooling to the cooling coils (CC), without running thecompressor for a significant number of hours each year. The HEDS CCsizing is such that the “cold” water temperatures can be very high whilestill providing enough cooling energy to keep the facility cool. Duringthe spring, in many locations, it is likely that the compressor will notbe run until the humidity levels get too high, or the water temperatureavailable from the earth-source is just below the desired dewpointtemperature. With these system implementations, compressor run time canbe minimized, extending equipment life and reducing energy waste. Whendehumidification is needed, the cold water temperatures being withdrawnfrom the earth loop can be as close as 2° F. to the desired dewpointtemperature of the air being supplied by the unit. Even as the coolingsource energy is warmed up, there may be many hours a day when thecooling and/or cooling/dehumidification loads can be met with directearth-sourced cooling, rather than compressor-augmented earth-sourcedcooling.

Similarly, during the fall, when heating loads may be low, and the watertemperatures available from the earth-sourced system are the highest, itis likely that the compressor will not need to be run to create heatinghot water to meet facility or process needs, heating energy can bedirectly sourced from the earth fields.

There will be many hours when the cooling augmentation system can beutilized to provide chilled fluid to the HEDS CC 1-0015 to meet coolingneeds without compressor operation, and the heating augmentation systemcan be utilized to provide warmed fluid to the HEDS CC 1-0015 to meetcooling needs without compressor operation, further reducing compressorrun time and extending equipment life.

If this system is combined with Underground Thermal Energy Storage(UTES), Aquifer Thermal Energy Storage (ATES), or Borehole ThermalEnergy Storage (BTES), the ability to utilize earth-sourced heating andcooling energy directly to meet facility or process needs, without theneed to operate the compressor(s) to augment the temperatures isenhanced even further.

The system is shown to use closed loop systems on both sides of the heatpump 1-1300. With appropriate equipment and filtration, open loop can beutilized, where allowed, for the earth-sourced side of the system.

The system allows simultaneous heating and cooling using 100% recoveredenergy, for any or all loads connected to the system. Some loads may bein heating only, some may be cooling only, and some may be incooling/dehumidification/reheat. Cooling and heating energy can bestored in the earth even when the compressor(s) are not running.

The diagrams depict multiple piping and equipment configurations thatallow a multitude of different operating strategies and enhancedefficiency, capacity and energy storage to occur.

Implementations described herein can unload effectively and reliablydown to 0% (zero percent) cooling load while providing the desiredsupply air dry bulb and dewpoint temperatures required to meet internaltemperature, dewpoint and relative humidity conditions, where othersystems cannot perform these duties. This helps prevent biologicalgrowth from occurring.

While the use of HGBP to add load to the compressor with existingdesigns will keep them running under light loads, it may negativelyaffect system operations and reliability as described elsewhere in thisapplication.

Additionally, when HGBP is used to false load the compressor to keep itoperational, there is no corresponding improvement in efficiency due tohead pressure relief. With the systems described herein, reducedrefrigerant pressures in the condenser result, as the heat is rejectedto create the false load, which lowers the fluid temperature of thereturn stream that is used to cool the refrigerant in the condenser.Removing heat from the heat rejection system via the preheat coil and/orreheat coil to false load the compressor or control temperatures or RHreduces the refrigerant pressure in the condenser, improving energyefficiency and capacity.

These implementations are unique in at least that by using heat rejectedfrom the compressor system via the preheat and reheat coils, or bydirect injection into the CHWR line to the plant to false load thecompressor, the condenser cooling liquid temperature can be reduced in ameaningful manner. This allows the head pressure (condenser siderefrigerant pressure) to be reduced with essentially zero energyexpended, improving compressor and system capacity and efficiency.

As an example: Assume that the ambient conditions are >55° F. and <60°F. and it is foggy or high humidity outside. The facility wouldtypically be in the heating mode of operation, but if heating isprovided without cooling and dehumidifying the air, the indoorconditions will have unacceptably high relative humidity, especially ifthe spaces are only heated to 68° F. as is the case with manyfacilities. To solve this problem, the fresh air being brought into thebuilding needs to be sub-cooled down to 55° F. or lower and thenreheated to some degree for most buildings to maintain the desiredindoor RH levels. The cooling load of the fresh air being brought intothe building is very small, too small for cooling systems to reliablyserve, so the compressor serving that cooling load will cycle on andoff. Every time the compressor cycles on, the cooling capacity is toohigh, even with Hot Gas ByPass (HGBP) or other false-loadingtechnologies, so the air is overcooled, and the coil fin pack is loadedwith a significant amount of condensed moisture. Because the supply airtemperature is too low, the compressor cycles back off, in short order.Now, when the compressor cycles off, the near 100% RH fresh air beingbrought into the building is untreated, and in fact may bere-evaporating the moisture that is being held in the coil fin pack, soRH control of the spaces is lost. When this situation occurs withvarious implementations of these inventions, those very low loads can bemet and controlled successfully. To ensure that the compressor does notcycle on and off and create RH and temperature control issues, load, inthe form of rejected heat energy from the condenser side of the system,would be injected either upstream from the cooling coil in the preheatcoil (PHC) to warm up the air entering the CC, or, in the absence of theneed for a preheat coil, heat would be injected into the chilled fluidloop, to add load directly to the system. The controls would be enabledto keep the compressor operational with minimal to zero on/off cycling.If this situation occurs when there is fluid available from the earthloop or the HCRU's or the cooling augmentation system at a low enoughtemperature, the compressor would not be enabled at all, and the loadswould be met directly through the use of the various piping, valve andpumping arrangements that interconnect the two sides of the system.

Multiple Heating/Cooling Recovery Units (HCRU) are shown. These devicesare unique in at least that they can either recover heating or coolingenergy from the piping loop to serve another load, or they can injectheating or cooling energy into the piping loop from other sources.

In some embodiments, the source of some or all of the cooling andheating energy could be the domestic water system.

The point of connection (POC) for the PHC and RHC could also be reversedif it is desired to have a higher quality heat available for the RHC toheat the air up to a higher temperature and to lower the RH of the airleaving the unit even further.

The earth-coupled field 1-2040 is shown to be connected into the pipingloop in two different locations, although additional locations can beincluded as needed to meet the needs of the system. The two piping POC'sthat are shown allow the capacity of the ground field to be augmentedand utilized in novel ways. During summer heat rejection to the ground,the heating energy going into the ground can either be decreased byrejecting heat to the atmosphere via the cooling augmentation system, orit can be increased by adding heat from another source, potentiallyrenewable or reclaimed from another waste heat source.

During the winter, or heating season, added cooling energy can beobtained to augment the cooling earth source for the following coolingseason. The earth-coupled field 1-2040 piping connections upstream fromthe augmentation systems can be used when the heat sink (or source) doesnot have enough instantaneous capacity and needs to be augmented to meetcurrent needs. The downstream piping POC can be used when it is desiredto augment the capacity of the heat sink (source) for the followingseason (or day).

Another unique part of the system described herein is the at least twosets of valves 1-4100 that provide two functions (see, e.g., FIG. 21 ).During the cooling season, especially at the start of the coolingseason, on the earth-loop side of the piping system, there may be fluidbeing delivered from the earth loop into the condenser side of thesystem that is too cold to allow proper operation of the compressorsystem—the refrigerant pressure could be too low to allow properrefrigerant flow volumes and orifice/expansion valve operation to occur,so the system may fault and fail on a frequent basis. The earth looppumping system will typically be variable flow, and to controlrefrigerant head pressure when excessively cold fluid is available, thepump speed will be modulated to its minimum flow setpoint. If theminimum flow from the earth loop is still too high, and the condensingpressure is too low, the pump flow rate would need to be reducedfurther, but the condenser heat exchangers have a minimum required flowrate through them. One of the valves performs two functionssimultaneously, and is modulated to control both head pressure andminimum flow rate through the condenser heat exchanger system.

Another set of valves 1-4102 is utilized to completely bypass thecondenser side (described for the cooling mode) of the heat pump, whenthere is the ability to utilize the cooling or heating energy stored inthe earth loop, or available from the HCRU's or heating or coolingaugmentation systems without the compressor being operated.

On the evaporator side of the heat pump (load side during the coolingmode) there is a similar set of valves that allows the evaporator to becompletely bypassed to allow cooling or heating energy to be distributedon the load side of the system without the need to operate thecompressor(s), or experience the pressure drop through the heatexchanger, as well as providing fluid recirculation from the leavingside of the evaporator to the entering side of the evaporator for bothtemperature control and flow control. Especially at the start of theheating season, the fluid temperature leaving the earth-source may betoo high for proper compressor/chiller/heat pump operation. If the fluidtemperature into the chiller is too high, these valves will becontrolled in a manner to recirculate cold leaving water into the warmto hot entering water to reduce the water temperature into the chiller.

With this and other hydraulic diagrams, pressure relief valves are notshown, but may be required to any section of piping or equipment thatcan be isolated between two valves without direct hydraulic access to anexpansion tank.

FIG. 23 is another embodiment of the current subject matter and depictsa cooling/heating plant based on standard chiller systems, which doesnot require a heat pump to perform heat recovery duties. The design isbuilt to provide relative humidity control, even down to 0% coolingloads, using standard chillers. Utilizing existing chillers, or standardchiller designs can happen due to the ability of the HEDS equipment toutilize very low quality heat during the heating season, so the chillersdo not have to be designed for high lift, high water temperatureconditions. This will allow existing cooling/heating systems to beutilized vs. having to install completely new refrigeration and heatingequipment to perform heating/cooling/dehumidification/reheat duties forfacilities.

Piping and valving are shown that allow the cooling and heating flowsthrough the equipment to be swapped, so that the load can either beprovided with cooling or heating from either set of piping. The flowscould also be reversed thru the heat exchangers when the switchovertakes place.

The loads can still be simultaneously served with heating and coolingdirectly off of the chiller, and the same type of earth coupled fieldand cooling and heating energy recovery and augmentation systems can beutilized as is shown in FIGS. 21 and 22 .

The functionality of this implementation essentially mirrors thefunctionality available with FIGS. 21 and 22 , the main difference beingthat existing, or standard design chillers can be utilized with thisimplementation.

FIGS. 24A and 24B depicts an abbreviated system architecture for thecontrol system 300 that controls sequences of operation describedherein. For example, the control system that controls the AHUs (andvarious components thereof) and/or the plants coupled with the AHUs mayinclude various control sequences that are performed using variousinputs (e.g., input devices 340, which may include Internet of Thingsconnections).

In some implementations, the control system measures and/or collectsvarious weather-related inputs that may be used in the setpointprediction sequences and control methods to proactively respond tochanges before the changes occur and to enhance the response to changesthat occur. The control methods associated with these inputs determinewhere the controlled variable setpoints will need to be based onhistorical data and the weather forecast. Once the control systemdetermines where the variables need to be, the setpoints for thecontrolled variables may be used to modulate the equipment and systemsthat are responsible for controlling those variables. In someimplementations, weather related inputs (e.g., input devices 340)include: Actual Weather, Weather Forecast, Historical Weather,Historical System Set points and actual variable conditions, Historicalindoor conditions and condition setpoints, Historical Occupancy, andHistorical Production.

In some implementations, the control system measures and/or collectsvarious weather-related inputs that may be used to determine thespecific needs that must be met by the HVAC/HEDS system and supportingequipment. Deviations from setpoints, modes, time of day, day of week,ambient conditions, and the like may all factor into the systemresponses to maintain facility or process conditions. The inputs mayinclude and/or may be received by the control system from: Building MassTemperature Sensors, Building moisture content (in various indoorlocations), Dry bulb temperature (in various indoor and outdoorlocations), Wet bulb temperature (in various indoor and outdoorlocations), Dew point temperature (in various indoor and outdoorlocations), Relative humidity (in various indoor and outdoor locations),and Humidification systems.

In some implementations, there are several methods to control the RH ofthe air in a space. The air volume being delivered to the space can beincreased or decreased, the dewpoint temperature of the air beingdelivered to the space can be increased or decreased, and the dry bulbtemperature of the air being delivered to the space can be increased ordecreased. The control methods performed by the control system describedherein may be performed individually, or concurrently to provide thedesired effect of changing the relative humidity level in theconditioned space or process load.

Decrease Dewpoint Temperature to Reduce RH

If the control system associated with RH control determines that thedewpoint temperature being delivered to the space/process needs to bereduced to create a lower relative humidity level, the control systemwill modulate the various components of the system to create a lowerdewpoint temperature. For any given drybulb temperature of air, a lowerdewpoint temperature will result in a lower RH level. If the dewpointtemperature is being controlled in direct response to changes in thedewpoint of the conditioned spaces, rather than via a change in the RH,the control system described herein also applies.

In some embodiments, there are valve(s) (such as the valveconfigurations described herein) that control the flow (mass flow rate)of the chilled fluid being sent through the cooling coils (C/C) 1-0015.In order to decrease the dewpoint temperature, the valves may bemodulated to increase the flow of chilled fluid passing through the C/C1-0015. This higher volume of chilled fluid reduces the averagetemperature of the fluid within the heat transfer tubes. The loweraverage temperature of the fluid within the tubes reduces thetemperature of the air passing over the coils to a greater extent, whichwill condense more moisture out of the air, thus reducing the dewpointtemperature.

In some embodiments, the control system communicates with variablespeed/variable flow fluid pumping systems that control the flow (massflow rate) of the chilled fluid being sent through the cooling coils(C/C) 1-0015. In order to decrease the dewpoint temperature, the controlsystem may modulate the pump speed to a higher speed, to increase theflow of chilled fluid passing through the C/C 1-0015. This higher volumeof chilled fluid will reduce the average temperature of the fluid withinthe heat transfer tubes. The lower average temperature of the fluidwithin the tubes will reduce the temperature of the air passing over thecoils to a greater extent, which will condense more moisture out of theair, thus reducing the dewpoint temperature. The pump speed can bemodulated by the control system directly, or via the use of anintermediate step (e.g., modulating the setpoint for the chilled watersystem differential pressure). A higher differential pressure setpointwill increase the pump speed, while a lower differential pressuresetpoint will decrease the pump speed.

In some embodiments, the control system communicates with coolingsystems/chillers that control the temperature of the chilled fluid beingsent through the cooling coils (C/C) 1-0015. In order to decrease thedewpoint temperature, the chilled water supply temperature setpoint willbe reduced, and the cooling system/chiller (such as via the controlsystem) will modulate to a higher capacity. The higher available coolingsystem/chiller capacity will reduce the temperature of the fluid beingsupplied to the C/C 1-0015. This lower chilled fluid temperature willreduce the average temperature of the fluid within the heat transfertubes. The lower average temperature of the fluid within the tubes willreduce the temperature of the air passing over the coils to a greaterextent, which will condense more moisture out of the air, thus reducingthe dewpoint temperature.

In some embodiments, the control system communicates with variablespeed/variable flow air delivery/fan systems that control the flow (massflow rate) of the air being sent through the cooling coils (C/C) 1-0015and into the conditioned spaces or process loads. In order to decreasethe dewpoint temperature, the control system may modulate a volume ofair passing through the cooling coil 1-0015 to a lower volume, todecrease the flow of air passing through the C/C 1-0015. In someimplementations, if no other changes occur, this lower volume of airwill reduce the average temperature of the air passing over the heattransfer tubes. The lower average temperature of the air passing overthe tubes will condense more moisture out of the air, thus reducing thedewpoint temperature.

Similarly, the control system can modulate fan speed command to delivera higher volume of air. Sending a higher volume of air into the load bymodulating the fan speed to a higher level, without changing thedewpoint temperature of the air being delivered to the conditionedspaces/process loads may also result in the RH levels being reduced. Thefan speed can be modulated directly, or via the use of an intermediatestep (e.g., modulating the setpoint for the supply air distributionsystem static/differential pressure). A higher static/differentialpressure setpoint will increase the fan speed, while a lowerdifferential pressure setpoint will decrease the fan speed.

Increase Dry Bulb Temperature to Reduce RH

If the control system associated with RH control determines that thedrybulb temperature being delivered to the space/process needs to beincreased to create a lower relative humidity level, the control systemwill communicate with the various components of the system to create ahigher drybulb temperature. For any given moisture content level of air,a higher dry bulb temperature will result in a lower RH level.

In some embodiments, the control system controls one or more valves thatmay control the flow (mass flow rate) of the warmed fluid being sentthrough the cooling recovery coils (CRC), sometimes referred to as theEnergy Recovery Coil or ERC (e.g., the CRC 1-0030). In order to increasethe drybulb temperature, the control system may modulate the valve toincrease the flow of warmed fluid passing through the CRC 1-0030. Thishigher volume of warmed fluid will increase the average temperature ofthe fluid within the CRC 1-0030 heat transfer tubes. The higher averagetemperature of the fluid within the CRC 1-0030 tubes will increase thetemperature of the air passing over the coils to a greater extent, thusincreasing the drybulb temperature.

In some embodiments, the control system communicates with one or morevariable speed/variable flow fluid pumping systems that control the flow(mass flow rate) of the warmed fluid being sent through the CRC 1-0030.In order to increase the drybulb temperature, the control system maymodulate pump speed to a higher speed, to increase the flow of warmedfluid passing through the CRC 1-0030. This higher volume of warmed fluidwill increase the average temperature of the fluid within the heattransfer tubes. The higher average temperature of the fluid within thetubes will increase the temperature of the air passing over the coils toa greater extent, thus increasing the drybulb temperature. The pumpspeed can be modulated directly, or via the use of an intermediate step(e.g., modulating the setpoint for the system differential pressure). Ahigher differential pressure setpoint will increase the pump speed,while a lower differential pressure setpoint will decrease the pumpspeed.

In some embodiments, the control system communicates with one or morecooling systems/chillers that indirectly control the temperature of thewarmed fluid being sent through the cooling recovery coils (CRC) 1-0030.Since the CRC 1-0030 relies on the approach temperature between thewarmed fluid inside the coils and the air being delivered through thecoils to raise the dry bulb temperature of the air, obtaining thehighest quality heat (highest temperature), can increase theeffectiveness, and thus the air temperature, leaving the CRC 1-0030. Insome implementations, providing colder chilled water to the C/C 1-0015will result in a lower volume of water being required to meet the loadsserved by the C/C 1-0015, but the fluid temperature leaving the C/C1-0015 will be at a higher level, assuming that the C/C is undercontrol. In order to increase the drybulb temperature of the air leavingthe CRC 1-0030, the chilled water supply temperature setpoint may bereduced (e.g., by the control system), and the cooling system/chiller(such as via the control system) may modulate to a higher capacity. Thehigher available cooling system/chiller capacity will reduce thetemperature of the fluid being supplied to the C/C 1-0015. This lowerchilled fluid temperature entering the C/C 1-0015 may increase thetemperature of the fluid leaving the C/C 1-0015 (e.g., assuming aconstant load on the C/C). The higher CRC entering fluid temperature mayincrease the average temperature of the fluid within the CRC heattransfer tubes. The higher average temperature of the fluid within thetubes may increase the temperature of the air passing over the coils,thus increasing the drybulb temperature.

In some embodiments, the control system communicates with one or morevariable speed/variable flow air delivery/fan systems that control theflow (mass flow rate) of the air being sent through the cooling coils(C/C) 1-0015 and into the conditioned spaces or process loads. In orderto increase the drybulb temperature, the volume of air passing throughthe cooling coil will be modulated to a lower volume, to decrease theflow of air passing through the C/C. The C/C fluid flowrate may bemodulated to a lower level (such as by the control system) (e.g.,assuming that the dewpoint temperature setpoint for the C/C remainsunchanged), which may result in a higher quality warmed fluidtemperature leaving the C/C. The reduced air volume passing through theC/C 1-0015 reduces the loads on the C/C 1-0015, so the chilled fluidflow rate is reduced further, again, resulting in a higher qualitywarmed fluid temperature being available to the CRC 1-0030. The reducedair flow rate may also result in the dry bulb temperature of theconditioned spaces warming up on their own, due to the reduced coolingcapacity available to remove the sensible heat from the spaces. Thislower volume of air passing over the CRC coils, and the higher qualityheat inside the CRC tubes, may increase the average temperature of theair passing over the heat transfer tubes. The higher average temperatureof the air passing over the tubes may reduce the RH level.

Similarly, the control system may modulate fan speed command to delivera higher volume of air. Sending a higher volume of air into the load bymodulating the fan speed to a higher level, without changing thedewpoint and drybulb temperature of the air being delivered to theconditioned spaces/process loads may also result in the RH levels beingreduced. The fan speed can be modulated directly, or via the use of anintermediate step (e.g., by modulating the setpoint for the supply airdistribution system static/differential pressure). A higherstatic/differential pressure setpoint will increase the fan speed, whilea lower differential pressure setpoint will decrease the fan speed.

Increase Dewpoint to Increase RH

If the control system associated with RH control determines that thedewpoint temperature being delivered to the space/process needs to beincreased to create a higher relative humidity level, the control systemmay communicate with the various components of the system to create ahigher dewpoint temperature. For any given drybulb temperature of air, ahigher dewpoint temperature will result in a higher RH level.

In some embodiments, the control system communicates with valve(s) thatcontrol the flow (mass flow rate) of the chilled fluid being sentthrough the cooling coils (C/C) 1-0015. In order to increase thedewpoint temperature, the valve may be modulated to decrease the flow ofchilled fluid passing through the C/C 1-0015. This lower volume ofchilled fluid may increase the average temperature of the fluid withinthe heat transfer tubes. The higher average temperature of the fluidwithin the tubes may increase the temperature of the air passing overthe coils to a greater extent, which may condense less moisture out ofthe air, thus increasing the dewpoint temperature.

In some embodiments, the control system communicates with one or morevariable speed/variable flow fluid pumping systems that control the flow(mass flow rate) of the chilled fluid being sent through the coolingcoils (C/C) 1-0015. In order to increase the dewpoint temperature, thepump speed may be modulated to a lower speed, to decrease the flow ofchilled fluid passing through the C/C 1-0015. This lower volume ofchilled fluid may increase the average temperature of the fluid withinthe heat transfer tubes. The higher average temperature of the fluidwithin the tubes may increase the temperature of the air passing overthe coils to a greater extent, which may condense less moisture out ofthe air, thus increasing the dewpoint temperature. The pump speed can bemodulated directly, or via the use of an intermediate step (e.g.,modulating the setpoint for the chilled water system differentialpressure). A higher differential pressure setpoint will increase thepump speed, while a lower differential pressure setpoint will decreasethe pump speed.

In some embodiments, the control system communicates with coolingsystems/chillers that control the temperature of the chilled fluid beingsent through the cooling coils (C/C) 1-0015. In order to increase thedewpoint temperature, the chilled water supply temperature setpoint maybe increased, and the cooling system/chiller may be modulated (e.g., bythe control system) to a lower capacity. The lower available coolingsystem/chiller capacity may increase the temperature of the fluid beingsupplied to the C/C 1-0015. This higher chilled fluid temperature mayincrease the average temperature of the fluid within the heat transfertubes. The higher average temperature of the fluid within the tubes maydecrease the temperature of the air passing over the coils to a lesserextent, which may condense less moisture out of the air, thus increasingthe dewpoint temperature.

In some embodiments, the control system communicates with one or morevariable speed/variable flow air delivery/fan systems that control theflow (mass flow rate) of the air being sent through the cooling coils(C/C) 1-0015 and into the conditioned spaces or process loads. In orderto increase the dewpoint temperature, the volume of air passing throughthe cooling coil may be modulated (e.g., by the control system) to ahigher volume, to increase the flow of air passing through the C/C1-0015. If no other changes occur, this higher volume of air mayincrease the average temperature of the air passing over the heattransfer tubes. The higher average temperature of the air passing overthe tubes may condense less moisture out of the air, thus increasing thedewpoint temperature.

Similarly, the fan speed command can be modulated (e.g., by the controlsystem) to deliver a lower volume of air. Sending a lower volume of airinto the load by modulating the fan speed to a lower level, withoutchanging the dewpoint temperature of the air being delivered to theconditioned spaces/process loads may also result in the RH levels beingincreased. The fan speed can be modulated directly, or via the use of anintermediate step (e.g., by modulating the setpoint for the supply airdistribution system static/differential pressure). A higherstatic/differential pressure setpoint may increase the fan speed, whilea lower differential pressure setpoint may decrease the fan speed.

Decrease Dry Bulb to Increase RH:

If the control system associated with RH control determines that thedrybulb temperature being delivered to the space/process needs to bedecreased to create a higher relative humidity level, the control systemwill communicate with the various components of the system to create alower drybulb temperature. For any given moisture content level of air,a lower dry bulb temperature may result in a higher RH level.

In some embodiments, the control system communicates with one or morevalves that control the flow (mass flow rate) of the warmed fluid beingsent through the cooling recovery coils (CRC) 1-0030, sometimes referredto as the Energy Recovery Coil or ERC. In order to decrease the drybulbtemperature, the valve may be modulated (e.g., by the control system) todecrease the flow of warmed fluid passing through the CRC 1-0030. Thislower volume of warmed fluid may decrease the average temperature of thefluid within the CRC 1-0030 heat transfer tubes. The lower averagetemperature of the fluid within the CRC 1-0030 tubes will increase thetemperature of the air passing over the coils to a lesser extent, thusdecreasing the drybulb temperature.

In some embodiments, the control system communicates with one or morevariable speed/variable flow fluid pumping systems that control the flow(mass flow rate) of the warmed fluid being sent through the CRC 1-0030.In order to decrease the drybulb temperature, the pump speed may bemodulated (e.g., by the control system) to a lower speed, to decreasethe flow of warmed fluid passing through the CRC 1-0030. This lowervolume of warmed fluid may decrease the average temperature of the fluidwithin the heat transfer tubes. The lower average temperature of thefluid within the tubes may increase the temperature of the air passingover the coils to a lesser extent, thus decreasing the drybulbtemperature. The pump speed can be modulated directly, or via the use ofan intermediate step (e.g., by modulating the setpoint for the systemdifferential pressure). A higher differential pressure setpoint willincrease the pump speed, while a lower differential pressure setpointwill decrease the pump speed.

In some embodiments, the control system communicates with one or morecooling systems/chillers that directly or indirectly control thetemperature of the warmed fluid being sent through the cooling recoverycoils (CRC) 1-0030. Since the CRC 1-0030 relies on the approachtemperature between the warmed fluid inside the coils and the air beingdelivered through the coils to raise the dry bulb temperature of theair, obtaining the highest quality heat (highest temperature), canincrease the effectiveness, and thus the air temperature, leaving theCRC 1-0030. In some implementations, providing colder chilled water tothe C/C 1-0015 may result in a lower volume of water being required tomeet the loads served by the C/C 1-0015, but the fluid temperatureleaving the C/C 1-0015 may be at a higher level (e.g., assuming that theC/C is under control). In this case, where the control system increasesthe CRC air temperature to a lesser extent, lower quality heat can beused to save chiller energy. In order to increase the drybulbtemperature of the air leaving the CRC to a lesser extent, the chilledwater supply temperature setpoint can be increased (e.g., by the controlsystem), and the cooling system/chiller will modulate (e.g., by thecontrol system) to a reduced capacity. The lower available coolingsystem/chiller capacity may increase the temperature of the fluid beingsupplied to the C/C 1-0015. This warmer chilled fluid temperatureentering the C/C 1-0015 may decrease the temperature of the fluidleaving the C/C (e.g., assuming a constant load on the C/C 1-0015). Thelower CRC entering fluid temperature may decrease the averagetemperature of the fluid within the CRC heat transfer tubes. The loweraverage temperature of the fluid within the CRC tubes may increase thetemperature of the air passing over the coils to a lesser extent, thusincreasing the drybulb temperature.

In some embodiments, the control system communicates with one or morevariable speed/variable flow air delivery/fan systems that control theflow (mass flow rate) of the air being sent through the cooling coils(C/C) 1-0015 and into the conditioned spaces or process loads. In orderto decrease the drybulb temperature, the volume of air passing throughthe cooling coil may be modulated to a higher volume (e.g., by thecontrol system), to increase the flow of air passing through the C/C1-0015. The C/C fluid flowrate may be modulated to a higher level (e.g.,assuming that the dewpoint temperature setpoint for the C/C remainsunchanged), which may result in a lower quality warmed fluid temperatureleaving the C/C 1-0015. The increased air volume passing through the C/C1-0015 increases the loads on the C/C 1-0015, so the chilled fluid flowrate is increased further, again, resulting in a lower quality warmedfluid temperature being available to the CRC 1-0030. The increased airflow rate may also result in the dry bulb temperature of the conditionedspaces being raised, due to the increased cooling capacity available toremove the sensible heat from the spaces. This higher volume of airpassing over the CRC coils 1-0030, and the lower quality heat inside theCRC 1-0030 tubes may decrease the average temperature of the air passingover the heat transfer tubes. The lower average temperature of the airpassing over the CRC tubes may increase the RH level.

Similarly, the fan speed command can be modulated (e.g., by the controlsystem) to deliver a lower volume of air. This is most effective atraising the RH levels if there are significant sources of moisture beinggenerated in the spaces, or by moisture sources such as operable windowsand doors being left open or poor facility construction being present.Sending a lower volume of air into the load by modulating the fan speedto a lower level, without changing the dewpoint and drybulb temperatureof the air being delivered to the conditioned spaces/process loads mayresult in the RH levels being increased (e.g., if there are moisturegeneration sources such as those described above). The fan speed can bemodulated directly, or via the use of an intermediate step (e.g.,modulating the setpoint for the supply air distribution systemstatic/differential pressure). A higher static/differential pressuresetpoint may increase the fan speed, while a lower differential pressuresetpoint may decrease the fan speed.

In some implementations, the control system may control one or morecomponents of the systems described herein to anticipate increases anddecreases in the loads in specific areas of a facility and to directresources to those areas that will need more capacity, and reduceresource allocations to areas where the loads are dropping off. Forexample, the control system may receive inputs (e.g., input/outputdevices or systems, 340) from one or more of: Security Systems (e.g.,badge control for workers and their locations in the facility, motiondetectors to infer occupancy levels, window alarms and positions, dooralarms and positions, etc., Fire/life safety systems, Elevator controlsystems, Parking lot and parking garage gate control, entry and exitgates, parking garage and parking lot occupancy monitoring system,Lighting control systems, Motion sensors, Occupancy scheduling system,Occupancy counting systems, Occupancy heat maps, Historical occupancyheat maps, Equipment scheduling systems, Room or area scheduling system(industrial, offices, schools, colleges, universities), Productionscheduling systems, RFID system to plan for production increases anddecreases, Building mass temperature sensors, Building mass moisturesensors, and the like.

When the control system determines the desired direction of thecontrolled variables, the control system communicates with the variouscomponents of the systems, as described above. In some implementations,setpoints such as dewpoint temperature, dry bulb temperature, fan speedcommand, pump speed commands, differential pressure and static pressuresetpoints, and chilled water supply temperature setpoint can be variedpre-emptively to reduce swings in the conditioned spaces or processloads, (e.g., as would be the case in a reactive, rather thananticipatory control system).

In some implementations, the control system may control one or morecomponents of the systems described herein to control the HEDS units,chillers, boilers and support equipment to increase demand or decreasedemand based on signals from these various sources. To increase demand,the dewpoint temperature, RH and chilled water supply setpoints can bedecreased, and airflow rates, static pressure setpoints and condenserwater temperature or refrigerant temperature setpoints can be increased.To decrease demand, the opposite can occur. For example, in someimplementations, the control system may receive inputs (e.g., inputs340) from one or more of: Level of added demand requested, and durationof the event, Level of demand reduction requested, and the duration ofthe event, meter and submeter readings to provide feedback to thecontroller, Distributed Energy Resource Control System, Grid load shapecontrol system, Renewables control and monitoring systems, Power plantload and efficiency information to increase or decrease loads on thegrid, Local grid condition information to assist with load shaping,voltage and frequency control locally, Regional grid conditioninformation to assist with load shaping, voltage and frequency controlregionally, Electrical generator control systems—load, reserve load,efficiency, fuel consumption rate, frequency, voltage, amperage, exhaustgas temperatures, generator temperature and other information asrequired to optimize the use of the generators and their available fuelsources, Utility or Independent System Operator (ISO) inputs (e.g.,input devices 340) for: Voltage and frequency regulation —up and down,Demand reduction request and future reduction request, Demand increaserequest and future increase request, Anticipated need for demandreduction, Anticipated need for demand increase, Power quality, FacilityOwner/manager/operator/other 3rd party inputs for: Voltage and frequencyregulation —up and down, Demand reduction request and future reductionrequest, Demand increase request and future increase request,Anticipated need for demand reduction, Anticipated need for demandincrease, etc., Frequency sensors at main power feed to facility, attransformers within the facility, and at local and regional substations,Voltage sensors at main power feed to facility, at transformers withinthe facility, and at local and regional substations, Power qualitysensors at main power feed to facility, at transformers within thefacility, and at local and regional substations, Thermal sensors at mainpower feed transformer to facility, at transformers within the facility,and at various loads within the facility, Thermal energy storage andbattery energy storage and other forms of energy storage, and the like.

In some embodiments, the control system receives information from avariety of building systems and wired or wireless connections withelectrical grid and building electrical infrastructure related systems.The control system utilizes current and historical data to anticipatethe needs of the conditioned spaces or process loads, while varyingloads based on inputs (e.g., input devices 340) from the grid and othersystems. When the control system determines the desired direction of thecontrolled variables, the control system communicates with the systemsand equipment, as described above.

Setpoints such as dewpoint temperature, dry bulb temperature, fan speedcommand, pump speed commands, differential pressure and static pressure,and chilled water supply temperature setpoint can be varied by thecontrol system in a manner that provides benefit to the electrical gridand facility electrical infrastructure and utility costs, whileminimizing negative impacts on the facility, it's occupants and processloads.

The control system described herein, unlike typical demand response (DR)or Distributed Energy Resource (DER) control systems, includes theeffects of changing system setpoints on the RH and moisture content ofthe conditioned spaces. Utilizing the specialized control sequences andequipment described herein can allow for prolonged capacity reductionsthat still reduce the potential for biological growth to occur.

Traditional DR/DER systems may use brute force changes to the HVACsystem, such as shutting off one or more chillers, demand limiting thechillers, sending fan speed limitation commands or reduced staticpressure setpoints to fan speed controllers, raising the HVAC systemsupply air temperature setpoints, raising the chilled water supplytemperature, lowering the chilled water system differential pressuresetpoint or limiting the maximum pump speed commands. All of thesestrategies blindly increase the supply air temperature to the point thatminimal to no dehumidification occurs. When this occurs, the dewpointtemperature and RH in the conditioned spaces can increase to the pointthat biological growth is likely, if not guaranteed.

To decrease electrical demands, the control system described herein canperform various functions. For example, the fan speed may be capped bythe control system at various speeds—the lower the speed, the greaterthe demand reduction. The dewpoint temperature setpoint may be allowedto float higher than during normal operation, to be controlled tomaintain the space or return air RH at up to 65%, rather than maintain adesired dewpoint temperature. The CRC control system may fully reclaimenergy via the CRC 1-0030 and CRC2 1-0033. When combined with thereduced supply air volume and the increased dewpoint temperaturesetpoint, the full energy reclaim may significantly reduce the loads onthe chillers and fan systems, while still controlling RH. The controlsystem may analyze the outage and at set intervals (e.g., every 10hours), the control systems may reduce the space/return air RH setpoint(e.g., to 50%) for a period of time (all setpoints may be automaticallyand/or manually adjustable) to help break the germination/growth cyclesfor a variety of unwanted biologicals.

In some implementations, as deeper demand reductions are requested, thefan speeds may be limited in increasingly more aggressive manners. Forexample, the return air damper system may be closed completely, and theonly air being brought into the building may be the fresh air. In suchconfigurations, all of fresh air may pass through the HVAC equipment fordehumidification. In some implementations, the control system may shutoff the exhaust systems (e.g., where appropriate and safe), and minimizethe amount of fresh air brought into the building via adjusting one ormore dampers to adjust the level required to keep the buildingpositively pressurized. In some implementations, the control system maycompletely shut the HVAC system off, and at various time intervals(e.g., 10 hours), restart the systems to bring the space RH undercontrol.

In some implementations, the control system 300 may reduce powerconsumption to extend the available resources and fuel supplies. Variouslevels of demand and consumption curtailment may be utilized, based oninputs (e.g., input devices 340) from the affected systems, as well asadjustable setpoints. In some implementations, inputs may be received,such as CNG, LNG, LPG, propane, hydrogen, alcohol, petroleum, gasoline,diesel, biodiesel, methane, ethane, methanol, ethanol, butanol, ammoniaand other fuel storage systems, land based and maritime based systems,current and projected amounts of fuel available for power generation,propulsion, HVAC, lighting, general electrical loads, reheat/heating andcurrent/historical/projected fuel consumption rates to stretch theavailable fuel to meet the scheduled need for fuel to reduce thepossibility of running out of fuel, or running low on fuel, and thelike. In some implementations, such as for large ships, or vessels, thecontrol system may evaluate the projected time on station at current andhistorical fuel consumption rates, notify personnel of the projectedtime on station as compared to the desired time on station, and thelike. In some circumstances, if projected time on station is less thandesired time on station, the control system may automatically reset HVACand other equipment setpoints, and on/off status as needed to exceed thedesired time on station by an operator adjustable amount.

In some implementations, the control system 300 may evaluate currentfuel consumption, historical trends in fuel consumption and loads servedby the generation system and compare that information against currentlyavailable fuel reserves and anticipated refueling dates and refuelingquantities to determine how to adjust various variables, includingdewpoint temperature, drybulb temperature, flow rate, capacity, and thelike.

In some implementations, the control system may communicate with one ormore inputs (e.g., input devices 340), such as one or more water levelmonitoring systems, such as storage tanks, ponds, cooling tower basins,other vessels (e.g., low water level means to “produce more condensate”or “reduce chiller plant loads”). The control system 300 may determinewhere loads need to be supplied to meet desired water make up quantitiesand time availability duration. In some implementations, when addedwater is required, the dewpoint temperature setpoint and fan speedlimitation may be modulated by the control system in a manner that driesthe air out to a lower dewpoint setpoint, and provides a higher CFM, asmay be required, via means described herein.

In some implementations, the control system 300 may communicate withinput devices 340, such as water filters, reverse osmosis systems,distillation systems, UV light systems, and other purification systems.

In some implementations, the control system 300 may adjust setpoints todeal with the needs of the systems that provided the input data, such asfrom input devices 340. The input devices 340 may include HVAC optimizedstart/stop systems, Coasting cycle control systems, Low load shutdowncontrol system, Chiller failure alarm system, Chiller load recyclesystems, HVAC control and monitoring systems, Air sampling systems (CO2,particles, VOC's, other), visual monitoring systems, and the like.

In some embodiments, the control system includes an HVAC optimizedstart/stop system. The control system may evaluate the conditions at thetime of the requested start time and determine what the desired dewpointtemperature and drybulb temperatures are, and/or the fan speedlimitations. In some embodiments, if the facility is hot and humidinside, starting the fan system and delivering very cold air into theconditioned spaces may cause condensation to occur in the spaces. Insome implementations, the control system may modulate the fan speed,dewpoint and dry bulb temperature setpoints in a manner that dries thebuilding out quickly, such as by controlling the dewpoint temperaturesetpoint. For example, the control system may control the dewpointtemperature setpoint to be a few degrees (or more) above the chilledwater supply temperature entering the C/C 1-0015 to maximize moistureremoval from the space. The CRC dry bulb temperature may be controlledby the control system to provide a dry bulb temperature that is at leastseveral degrees above the dewpoint temperature of the return air orconditioned space. The fan speed may be controlled by the control systemto push as much air as possible. The fan speed may be limited by, forexample, the maximum fan speed on startup, the need to maintain the C/Cdewpoint temperature at its setpoint, and the need to maintain the CRCleaving drybulb temperature at its setpoint. If the dewpoint temperatureor dry bulb temperature exceed their setpoints, the fan speed may beslowed down by the control system.

In some embodiments, the control system 300 may include a coasting cyclecontrol system. The coasting cycle control system may allow the mainHVAC system equipment to be shut down or capacity limited at/near theend of the day, when loads are typically their lightest and dropping.The control system 300 may evaluate the dewpoint and RH conditions ofthe space or return air. If the dewpoint and space/return RH conditionsare under control, the fan speed command/static pressure setpoint may bemodulated by the control system to a position that reduces the CFM beingdelivered to the spaces by 15% to 50% or more. The C/C valves and/orsystem may be modulated by the control system to 100% open, filling theC/C 1-0015 with cold water. The CRC valves and/or system may bemodulated by the control system to maximum flow through the CRC 1-0030and CRC2 1-0033. In this manner, the C/C 1-0015, CRC 1-0030 and CRC21-0033 may be all filled with a volume of cold water that will allow themain chiller systems to be shut down, while flowing chilled water aroundthe facility, using the energy stored in the CHW loop, and the C/C1-0015, CRC 1-0030 and CRC2 1-0033 as the chiller-equivalent. In someembodiments, the system may not include the CRC2 1-0033.

In some embodiments, the control system includes a chiller failure alarmcontrol system. When a chiller failure occurs, the system may be putinto one of the electrical grid load shaping levels, depending on theseverity of the failure. Such configurations may prolong the ability ofthe HVAC system to provide moderately conditioned air to the desiredspaces, even in the event of an equipment failure.

In some implementations, the control system 300 may monitor one or morebuilding differential pressure sensors, which compare the pressureinside the building, in that location, to the pressure outside thebuilding. In some embodiments, the control system 300 is configured tomaintain a positive pressure when the facility is in acooling/dehumidification mode. The control system may maintain aslightly negative pressure if the facility is humidity controlled duringsub-freezing weather to reduce condensation in the wall and attic spacesfor some occupancy types.

In some implementations, the control system 300 may receive inputs frominput devices 340, such as Hospital system inputs, nurses call stations,room occupancy systems, IAQ feedback systems, scheduling systems forpatient rooms, pre-op, post op, operating rooms (OR's), types ofsurgeries being scheduled and the desired IAQ conditions for each room,relative pressurization needs for the surgeries being scheduled,occupied unoccupied status for each occupancy type, minimum and maximumCFM setpoints and minimum and maximum setpoint values for dry bulb, wetbulb, dew point and relative humidity for various hospital areas,ultraviolet (U.V.) light control systems, and other air sterilizationsystems, and the like. In some implementations, the control system 300may receive inputs from input devices 340, such as airport aircraftflight scheduling systems, aircraft size, passenger counts, and gatedoorway status.

Some additional typical HVAC problems that the implementations of thecurrent subject matter can resolve:

Cooling Coil Face Velocity is Too High Causing High RH and MoistureCarry Off from the Coils: HEDS systems described herein use low coolingcoil face velocities, typically less than 450 feet per minute.

Coils That are Too Tall Creates Problems—Condensate Stacking andMoisture Carry Off: HEDS systems described herein use cooling coils thatmay be vertically short. For example, the cooling coils may be less than30″ tall, but the height may be taller, such as if the coil length isgreater than 3× the coil height.

Cooling Coils That Are Too Small (Rows, Face Area, Surface Area): HEDSsystems described herein use large rows, face area, surface area.

Condensate Stacking in the Coil/Condensate Carry-Off From the Coil: HEDSsystems described herein eliminate condensate stacking—shorter verticalheight, wider fin spacing, greater drainage area, intermediate drainpans

Lack of Intermediate Drain Pans: HEDS systems described herein may beequipped with intermediate drain pans

Low Delta T Syndrome is a Contributor to Mold Growth Caused by HVACsystems: HEDS systems described herein solve Low Delta T Syndrome byproviding higher than “normal” chilled water system temperaturedifferentials. Cooling Coil load TD's are typically in excess of 17° F.,and can exceed 30° F.

Building Pressurization with Low RH Air Must Occur Continuously DuringHumid Days: HEDS systems described herein maintain buildingpressurization with low RH air in the building.

Vapor Migration Into Buildings Is a Significant Problem: HEDS systemsdescribed herein reduce vapor migration into buildings by, for example,keeping them positively pressurized, and keeping the air in the facilityat a low RH level, below 60%.

Not Treating Dehumidification Loads at the Source: HEDS systemsdescribed herein treat dehumidification loads at the source to reduce RHin the conditioned spaces

Supply Air Relative Humidity in the Supply Ducts is Too High: HEDSsystems described herein lower duct air Relative Humidity, such as byinjecting heat at the AHU via the CRC.

Over-Cooling of Spaces Creates Problems: HEDS systems described hereineliminate space overcooling related to RH control, by using reclaimedenergy from the chilled water cooling coil (CC, or C/C) leaving water asthe primary reheat heating source.

Constant Air Volume (CAV) Systems Create Problems: CAV with HEDS systemsdescribed herein eliminates these problems, HEDS provides free reheat,by, for example, using reclaimed energy from the chilled water coolingcoil (CC, or C/C) leaving water as the primary reheat heating source.

Standing Water in Drain Pans Causes Mold Growth: HEDS systems describedherein use dual-sloped drain dry pan designs to ensure no standing waterremains in the drain pans.

Many Systems are Only Equipped with Pre-Heat Coils, Not Reheat Coils:HEDS systems described herein use preheat and reheat coils as needed, inaddition to the cooling coils and cooling recovery coils

Lack of Drain Pans in the Fresh Air/Mixed Air Plenums: HEDS systemsdescribed herein have drain pans in these locations

DX Compressor Cycling/Poor Controls: HEDS systems described herein canunload down to 0% load effectively

HVAC Fan Belts That Slip: HEDS systems described herein use direct drivemotors, no belts to slip.

HVAC DOAS or Fresh Air Make-up Fan Belts That Slip: HEDS systemsdescribed herein use direct drive motors, no belts to slip

Manual HVAC System Setpoint Over-rides: HEDS systems described hereininclude fail safe designs that provide reheat energy regardless ofmanual overrides or equipment failures

Radiant Panel and Active and Passive Chilled Beam Systems Can CreateProblems: HEDS systems described herein provide properly dehumidifiedair to reduce problems with these systems.

Chilled Water Based System Airside Temperature Swings Creates Problems:HEDS systems described herein include a failsafe design that ensureslower RH air leaves the unit, and has logic to reduce leaving airtemperature swings.

Undersized Ductwork Causes Low Supply Air Temperature Requirement: HEDSsystems described herein can provide low dewpoint, lower RH air to aspace, so loads can be met with less CFM (e.g., dry air feels coolerthan “wet” air).

Undersized VAV Boxes Causes Low Supply Air Temperature Requirement: HEDSsystems described herein can provide low dewpoint, lower RH air to aspace, so loads can be met with less CFM (e.g., dry air feels coolerthan “wet” air).

Supply Air Reheat Non-Existent, or Not Being Used: HEDS systemsdescribed herein can provide low dewpoint, lower RH air to a space, newreheat energy is minimized or eliminated by, for example, usingreclaimed energy from the chilled water cooling coil (CC, or C/C)leaving water as the primary reheat heating source.

Chiller Plants That Are Too Small: HEDS systems described hereinincrease effective chiller plant capacity by 18% to 37%

Chilled Water Piping That is Too Small: HEDS systems described hereincan deliver>two times the BTU's per gallon of fluid delivered,essentially doubling the pipeline capacity

Undersized Air Cooled Condensers Cause High Supply Air Temperatures andLack of RH Control: HEDS systems described herein reduce cooling loadsby 18% to 37%, taking load off of the condenser.

Chillers Overshooting Setpoint on the Low Side or High Side: HEDSsystems described herein provide lower RH air, and may havesignificantly greater fluid mass within them, reducing effects ofchilled fluid temperature swings

Chillers That Don't Unload Below 30% to 40% Capacity: HEDS systemsdescribed herein have the ability to false load the chillers toreduce/eliminate low load cycling problems

Chilled Water Supply Temperature “Optimization” Software can Contributeto Mold Growth: HEDS systems described herein seek first to meet RH andtemperature requirements, then save energy. HEDS optimization resets donot generally allow the dewpoint or RH to get out of control.

Lack of or Improper Use of Chilled Water System Differential PressureReset Logic: HEDS systems described herein seeks first to meet dewpointtemperature, RH and temperature requirements of the conditioned spacesor process loads, then save energy. The HEDS differential pressuresetpoint reset sequence may be based on meeting the needs of the HEDS CCand CRC coil systems, which are based on meeting temperature, dewpointand RH conditions required by the conditioned spaces or process loads.

Lack of or Improper Use of Chilled Water Supply Temperature Reset Logic:HEDS systems described herein seeks first to meet dewpoint temperature,RH and temperature requirements of the conditioned spaces or processloads, then save energy, the chiller chilled water supply temperaturesetpoint reset sequence may be based on meeting the needs of the HEDS CCand CRC coil systems, which are based on meeting temperature, dewpointand RH conditions required by the conditioned spaces or process loads.

HVAC Airside Optimization Software—Chilled Water Based Systems: HEDSsystems described herein seeks first to meet dewpoint temperature, RHand temperature requirements of the conditioned spaces or process loads,then save energy. The HEDS dewpoint temperature setpoint reset, dry bulbtemperature setpoint reset and fan CFM related resets may all be basedon meeting the needs of the HEDS CC and CRC coil systems, which arebased on meeting temperature, dewpoint and RH conditions.

Direct Expansion (DX) System Cycling/Staged Control Creates Problems:HEDS systems described herein has the ability to false load the chillersto reduce/eliminate low load cycling problems

Common Residential, Barracks, Dorm, Hotel, Apartment Complex HVACDesigns Create Situations for Mold Growth: HEDS systems described hereincan help to eliminate HVAC-caused mold growth

Water-Sourced Heat Pumps, Air Sourced Heat Pumps, Ground Coupled HeatPumps can all Create Situations for Mold Growth: HEDS systems describedherein can help to eliminate HVAC-caused mold growth

High Occupancy Zones that are Rarely Highly Occupied can CreateSituations for Mold Growth: HEDS systems described herein can providelow dewpoint, lower RH air to a space to reduce over-cooling and highspace RH issues

DX Systems that are Short of Refrigerant Charge, Or Over-Charged: HEDSsystems described herein reduces equipment capacity issues, and canunload down to 0% load. HEDS can be used to pretreat the fresh airentering DX or refrigerant based systems (and chilled water basedsystems), to reduce the effects of capacity issues related torefrigerant charge problems.

HVAC Airside Optimization Software—DX Compressor Based Systems: HEDSsystems described herein seeks first to meet dewpoint temperature, RHand temperature requirements of the conditioned spaces or process loads,then save energy. HEDS can be used to pretreat the fresh air entering DXor refrigerant based systems (and chilled water based systems), to allowrefrigerant based systems to only have to deal with sensible loads, andpotentially minimal latent loads, allowing the supply air temperaturesfrom the refrigerant based systems to be set much higher, reducing liftand saving energy.

DX Compressors That Are Too Big: HEDS systems described herein reducesequipment capacity issues, and can unload down to 0% load

Chillers That Are Too Big: HEDS systems described herein reducesequipment capacity issues, and can unload down to 0% load

Single Chiller Buildings: HEDS systems described herein reducesequipment capacity issues, and can unload down to 0% load

Constant Speed Chiller Compressors: HEDS systems described hereinreduces equipment capacity issues, and can unload down to 0% load

Two Pipe Chilled Water Distribution Systems Can Create Problems: HEDSsystems described herein provides reheat energy where there is no reheatenergy available by, for example, using reclaimed energy from thechilled water cooling coil (CC, or C/C) leaving water as the primaryreheat heating source.

Desiccant Wheel Equipment Failures Can Contribute to Mold Growth: HEDSsystems described herein provide low dewpoint, lower RH air to the loadsand have many less points of failure and maintenance needs.

Mixed Air Bypass Systems Can Create Problems: HEDS systems describedherein does not mix super-cooled air with mixed air that may have a highmoisture content, eliminating the potential for misting, fogging andcondensation to occur

Return Air Bypass Systems Can Create Problems: HEDS systems describedherein does not mix super-cooled air with return air that may have ahigh moisture content, eliminating the potential for misting, foggingand condensation to occur

Face-Split DX Coil Circuiting Creates Problems: HEDS systems describedherein does not mix super-cooled air with mixed air that may have a highmoisture content, eliminating the potential for misting, fogging andcondensation to occur

Sub-Cooling DOAS Without Reheat Can Create Problems: HEDS systemsdescribed herein intrinsically delivers low dewpoint, lower RH air tothe systems

Sub-Cooling DOAS Without Preheat Can Create Problems: HEDS systemsdescribed herein can unload further then typical DOAS units

Air to Air Heat Exchangers Can Create Problems in Humid Climates:Uncontrolled condensation and biological growth can occur in air to airHX systems, not in HEDS systems

Drain Pans do not Extend Below the Cooling Coil Headers: HEDS systemsdescribed herein include drain pans that extend below the cooling coilheaders

Condensation in the After-Filters Creates Problems: HEDS systemsdescribed herein can provide low dewpoint, lower RH air into theafter-filters to eliminate this issue

Demand Response/Grid Load Shaping Systems Can Create High Humidity andMoisture Carry off Problems: HEDS systems described herein can controlRH, even when in a Demand Response mode of operation.

FIGS. 25A-69 illustrate various configurations of AHUs and components ofAHUs, which may include any of the components described herein,including, but not limited to, the PHC 1-0026, the first CC #1 1-0015,the second CC #2 1-0015A, the first CRC 1-0030, the second CRC 1-0033,and the RHC 1-0027, among other components.

Coil Cleaning and Management

As noted above, as coils used in various HVAC systems, and their heattransfer fins age, corrosion, dirt and biological growth can furtherdegrade performance that was most likely inadequate in the first place,so the problems become worse over time. This can create situations wherecontrol systems are unable to maintain stable dry bulb temperature, dewpoint temperature and relative humidity control. Implementations of thecurrent subject matter can help to clean and maintain the coils andother equipment, extending the usable life of the equipment, whilereducing the overall size, weight and use of materials of the systems.

For example, AHUs in many harsh environments need to be replacedfrequently due to heat transfer coil and fin corrosion and failure.Equipment in coastal regions, for example, may only last 2 to 7 yearsbefore needing to be replaced. In many cases, the AHU casings, fans andother equipment have many additional years of life left in them, but thecoils fail, even coils that have had anti-corrosion treatments applied.If the coils were able to be cleaned and maintained on a regular basis,their life expectancy could be extended significantly. The constructionof the typical AHU's is such that replacing the coils is very difficult,and more costly than just replacing the entire unit, so significantnumbers of AHU's and many tons of steel, copper and aluminum are sent tothe trash dump needlessly.

Many facilities and locations that have significant dehumidificationloads do not receive properly conditioned air due to undersized orimproperly designed cooling coils. Proper dehumidification requires asignificant number of heat transfer tube rows to be built into eachcooling coil, whether it be liquid based or refrigerant based.

The subject matter described herein applies to all heat transfer coils,whether they be sourced by steam, hot water, chilled water, cool water,mixed phase refrigerants, liquid refrigerants, gaseous refrigerants orany other heat transfer fluid.

Many applications require at least 8, 10, 12 or more rows of heattransfer tubing and extended surface heat transfer fins. A low “fin perinch” count helps to reduce the dewpoint of the air, but may not provideadequate heat transfer surface area to reduce the sensible temperature(drybulb) far enough. When light cooling/dehumidification loads exist,if there is excessive heat transfer surface area available, and thecontrols are not properly configured, the system may be difficult tocontrol, and may over-cool the air, or swing between under-cooling andover-cooling, creating the need for excessive reheat energy to warm theair back up to meet comfort conditions or process needs.

Coils that have adequate depth (numbers of rows of heat transfer tubesand extended fin surface area) to meet the desired peak dehumidificationloads, may be unable to have their innermost rows cleaned, demineralizedand disinfected. ASHRAE recommends a maximum coil depth of 8 rows toallow proper cleaning and maintenance to occur. Depending on the findensity, 8 row, 6 row and even 4 row coils may not be able to beproperly maintained.

During typical dehumidification processes, solids can be deposited, andgelatinous materials and biological growth can occur on the heattransfer surface areas of the coil systems. With many applications,these materials may be un-cleanable and inaccessible with currentlyavailable designs and technologies.

These materials and biological growths reduce the available crosssection of the heat transfer surface area of the coil systems and cansignificantly increase the air velocity that is passing through the coilsystems. The increased air velocities and nature of the materials canlead to liquid water (condensate) being carried off of the fin surfacesand into the AHU, after-filters, ductwork or conditioned spaces,creating habitats for biological growth to occur.

For heat transfer coil systems with non-condensing loads, these sameproblems can still exist if the relative humidity and availability offood occurs, or if liquid water is deposited onto the heat transfersurface areas.

In rare occasions, Ultra Violet lights (e.g., Ultra Violet GermicidalIrradiation, UVGI) are incorporated into the AHU, typically downstreamfrom the cooling coils (such as in the configuration shown in FIGS. 1-19). UVGI may not reach very far into the heat transfer surface area, andthus may be ineffective at reducing most of the biological growth thatoccurs within the coil finned surface areas.

AHUs typically have significant distances between the individual coilsections to allow upstream and downstream access for cleaning, such asminimum distances of 18″ to 22″ (for short length coil sections) andto >36″ (for longer length coil sections), which may be used to allowpersonnel to have access to the interior of the unit for inspections andcleaning.

HVAC AHU equipment can be built for ease of maintenance, or for lowfirst cost, but not typically both. If the AHU is built to be easier tomaintain, it can be significantly longer, and thus more expensive thanthe least expensive AHU designs. One factor in driving the “ease ofmaintenance” AHU costs higher is the need to be able to clean the frontand back sides of the heat transfer coils, on a fairly frequent basis.Consistent cleaning may be required to maintain thermal performance, andto reduce the potential for biological growth, heat transfer fincorrosion and condensate being blown or pulled off of the cooling coilsand landing downstream in the AHU or ductwork systems. In order to beable to clean the coils easily, access doors are provided between eachcoil section to allow them to be observed and cleaned. In many cases,the access doors are 18″ clear width, which translates into a minimumdistance between coil casings of approximately 22″ in many cases.

Material costs are a driver of AHU costs. The longer the AHU, the higherthe costs. Overall length increases of an AHU, as driven by the need forspaces and access doors between coils can add significant costs to theAHU. The added length required by these access door sections can alsoincrease the required sizes of the mechanical spaces that house theAHU's. For example, if the AHU is roof mounted, or pad mounted, it canadd considerable costs to the structural supports or concrete equipmentpads. In many cases, there are existing mechanical spaces where AHU'sdesigned for ease of maintenance will not fit when it is time to replacethe installed equipment. If the current AHU is rooftop mounted, or in amezzanine, or in a multi-floor building, the added weight associatedwith the significantly larger AHU's designed for ease of maintenance candisallow them from being installed.

Various combinations of ductwork, plenums, louvers, dampers, fansystems, air filters and other typically required items in an HVACsystem can be located upstream or downstream or both from the coilsections shown.

Heat transfer coil sections and row counts are shown for depiction ofspecific coil combinations and are for illustrational purposes. Otherrow counts and configurations are also contemplated and may takeadvantage of the features of the current subject matter shown in thisthe figures and described herein.

Access doors or removable panel sections may be provided at each coilsection to allow easy access to the cleaning and flushing equipment forperformance of the cleaning process. The access doors and removablepanel sections are not shown in the figures.

The dimensions shown in FIGS. 25A-28B are shown for illustrationalpurposes, are estimates, and may vary based one or more variables,including the actual number of different coil sections, the number oftube rows in each coil section, the width of the coil cleaning accessareas, tube diameters, tube to tube centerline differences, and desireddrain pan configurations, and the like. The fluid inside the fluidconduits does not change the function and intent of the systems.Refrigerant based, water based or other fluid based heat transfer coilsall may be cleaned on their inlet and/or outlet sides.

In some embodiments, the systems can be used as an evaporative coolingsystem, by utilizing a clean water source and pumping, or otherwisecirculating the water over the heat transfer surface area during normaloperation. This has the added benefit of continually flushing solidsthat may have accumulated on the heat transfer surface of the coils.

At shutdown, the sump system would be drained, and the clean watersource would be fed over the surface area to lessen any residual solidsthat may have been present.

Chemically treated and/or lightly de-ionized water can be utilized tokill unwanted biological growth. The chemical systems and level ofde-ionization of the water must be compatible with the materials ofconstruction, as well as the occupancies of the spaces or process loadsbeing conditioned.

In hospital settings, or other settings where elimination of biologicalgrowth and elimination of airborne biologicals are critical, thecleaning cycle can be continuous, or as frequent as needed to obtain thedesired end result. Designing the coil systems for very low facevelocity will allow the process to be continuous if desired. Filtrationsystems for the recirculated fluids are included in the subject matterbut not shown.

In some embodiments, the subject matter can be used as a humidificationsystem, including preheat coils (such as the PHC 1-0026), cooling coils(such as the CC 1-0015), energy recovery coils (such as the CRC 1-0030,1-0033), reheat coils (such as the RHC 1-0027), and other heat transfercoils as may be required for the specific application.

Some implementations of the current subject matter include co-locatingthe coils in the same frame or frames (e.g., bolted together), back toback, with multiple ways to clean and disinfect the coils, and mayinclude coils in the middle of the coil banks that are typicallyinaccessible.

Implementations of the current subject matter address the needs toprovide the proper number of rows to provide the desireddehumidification levels, reduce overall unit length and cost whileenhancing the ability to maintain, clean and disinfect the entirety ofthe cooling coil, including both faces, and all of the rows in between,for example.

Implementations of the current subject matter address the need to reduceoverall unit length and cost while enhancing the ability to maintain,clean and disinfect the entirety of the other heat transfer coils,including both faces of each coil, and all of the rows in between.

Implementations of the current subject matter include the provision ofinsulated access panels that can be removed, to allow the cooling coilsystems and other heat transfer coil systems to be removed and replacedwith new heat transfer coils with relative ease, without damaging theremaining structure of the AHU. Access panels and access doors to allowthe coil cleaning slots to be easily usable are not shown for clarity,but may be included as a part of the various embodiments shown anddescribed.

FIG. 25A illustrates a depiction of an AHU coil configuration designedto extend the operational life of the equipment and enhance thermalperformance by incorporating typical maintenance access lengths. Asshown in FIG. 25A, the AHU coil configuration includes a two row (2R)Pre Heat Coil (PHC) 1-0026 that is 3″ deep, a 22″ wide access baybetween the coil casings, a ten row (10R) Cooling Coil (CC) 1-0015 thatis 15″ deep, a 22″ wide access bay between the coil casings, a six row(6R) Cooling Recovery Coil (CRC) 1-0030 that is 9″ deep, a 22″ wideaccess bay between the coil casings, and a four row (4R) Re-Heat Coil(RHC) 1-0027 that is 6″ deep, and has a total coil section length of99″. Other sizes and configurations are contemplated, as noted herein.

FIG. 25B illustrates a material optimized, resource efficient, coil banklayout that still allows the front and back of each of the coil sectionsto be accessed and cleaned. The same heat transfer row counts areincluded in FIG. 25B configuration as are in the FIG. 25A configuration.

In this implementation, the PHC 1-0026, CRC 1-0030 and RHC 1-0027 areall equipped with a two row (2R) wide access section, with removableplates shown as squares. The access section can be wider or narrowerthan depicted in FIG. 25B (as may be implemented for all depictions).The inlet side of the PHC 1-0026 is available for cleaning, typically byremoving the air filters from their frames. The downstream side of thePHC 1-0026 is available for cleaning by opening up the access panels onthe downstream side of the coil.

The inlet side of the CC 1-0015 may be accessed from the same openingsthat serve the discharge side of the PHC 1-0026. The downstream side ofthe CC 1-0015 may be available for cleaning by opening up the accesspanels on the downstream side of the coil. In some implementations, theinlet side of the CRC 1-0030 is accessed from the same openings thatserve the discharge side of the CC 1-0015. The downstream side of theCRC 1-0030 may be available for cleaning by opening up the access panelson the downstream side of the coil.

In some implementations, the inlet side of the RHC 1-0027 is accessedfrom the same openings that serve the discharge side of the CRC 1-0030.The downstream side of the RHC 1-0027 can either be accessed from theAHU discharge plenum, or by installing a RHC 1-0027 that is equippedwith the access panels on the inlet and discharge sides of the RHC1-0027. The access sections can be wider or narrower than depicted inFIGS. 25A-25B (and as shown in all of the depictions). Coils and accesspanels and openings can be combined in a variety of ways as may beneeded for constructability or performance issues. As shown in FIG. 25B,the configuration has a total coil section length of 42″, reducing thelength of the coil section by 57″, or 58%.

FIG. 25B depicts one embodiment that co-locates four distinct anddifferent heat transfer coil sections directly connected to one another,while providing access between each coil section for cleaning,observation and maintenance, and means and methods to introducecleaning, disinfecting and flushing agents into the mid sections of eachindividual coil section.

In this embodiment, Coil Section #1 (1-0026) is shown as a Pre Heat Coil(PHC) that can use new or reclaimed energy to preheat the air enteringthe unit. Even though it is shown as a PHC, the coil can be designed forany suitable duty for the specific application. This PHC 1-0026 canfunction as a freeze-protection device, a heating device, or as a meansto false load the cooling system compressors, so that additional heatcan be reclaimed from the heat rejection side of the cooling system, andused to warm up the air, potentially as a means to lower the RelativeHumidity (RH) of the air leaving the AHU and entering the spaces. It isshown as a two row coil, but can be any number of rows deep. The frameis shown as a standard four row frame, but the last two rows have notbeen punched for tubes, and access holes/panels/gaskets/covers have beenincluded to allow equipment such as cleaning wands, sprayers, brushes,lights and cameras to be inserted between the two coil sections to allowobservations to be conducted and maintenance to be performed. The coilframe can be any size, as long as there is adequate room for cleaning,flushing, observation and maintenance duties to be performed throughopenings in each side of the coil frame.

In some implementations, the co-location of the PHC 1-0026 in very closeproximity to the Coil Section #2 coil (e.g., CC 1-0015) allows the PHC1-0026 to perform freeze protection duties, even if the fan system hasbeen shut down or has failed. Radiant heat and convection provide heatto the fluid in the CC 1-0015, and air movement will be induced throughthe other coil sections as well, protecting them from freezing. Upondetermining that the airflow has been stopped or significantly reducedin an AHU, the control system will open the control valves on each heattransfer coil section and send notification to the heating and coolingsystems to start circulating water throughout each affected AHU. Thevalve on the PHC 1-0026 will be commanded to 100% open, and the hotwater supply temperature setpoint will be commanded to the maximumtemperature. This sequence is based on the ambient conditions beingbelow a user defined setpoint, initially set to be 40° F.

Coil Section #2 (1-0015) is shown as a cooling coil (but may include adifferent type of coil). It is shown as a 10 row coil, but can be anynumber of rows deep. The frame is shown as a standard 10 row frame. Thecoil frame can have access pathways as described in the 1-0026 coildescription and can be any size, as long as there is adequate room forcleaning, flushing, observation and maintenance duties to be performedthrough openings in each side of the coil frame.

The access holes/panels/gaskets/covers are shown as being located at theend of the coil section, but they could be mounted at the front of thecoil section, in the middle of the coil section, or towards the front orrear of the coil section. If the access holes/panels/gaskets/covers arelocated at other than the front or rear of the coil section, the heattransfer tubing or header systems must be designed to allow access forthe required equipment to occur.

More than one set of access holes/panels/gaskets/covers can be installedin each coil section. In one embodiment, a heating, cooling and energyrecovery system may have a 2 row PHC 1-0026, two 6 (six) row coolingcoils 1-0015, 1-0015A, a six row energy recovery coil 1-0030, and a tworow reheat coil 1-0027 required to meet their needs. To minimize theoverall length and cost of the unit, this configuration could beassembled as one coil section if desired, with accessholes/panels/gaskets/covers located between each of the individual coilsections.

In another embodiment, a twelve (12) row heat transfer coil may berequired to meet the desired temperature and moisture removal duties,with a six (6) row energy recovery coil located downstream that uses thewarmed up water from the CC chilled water return line to perform reheatduties. This could be built as three (3) coil sections of six (6) rowseach, with access holes/panels/gaskets/covers between each of the three6 row coils.

Coil Section #3 (1-0030) is shown as an energy recovery coil (e.g.,CRC). It is shown as a 6 row coil, but can be any number of rows deep.The frame is shown as a standard 8 row frame, but the last two rows havenot been punched for tubes, and access holes/panels/gaskets/covers havebeen included to allow equipment such as cleaning wands, lights andcameras to be inserted between the two coil sections to allowobservations to be conducted and maintenance to be performed. The coilframe can be any size, as long as there is adequate room for cleaning,flushing, observation and maintenance duties to be performed throughopenings in each side of the coil frame. If there were not accessholes/panels/gaskets/covers upstream from this coil, the frame could bea standard 10 row frame, with access holes/panels/gaskets/covers locatedupstream from, or in the middle of the 6 row active coil section. Inthis case, the energy is being recovered from the warmed up watersourced from the CC chilled water return line to perform reheat duties,but the heating energy could be provided by any source that has adequatecapacity and heat quality to perform the desired functionality. Theaccess holes/panels/gaskets/covers are shown to be square, but they canbe of any size, shape and location, with as many or as few as arerequired to perform the necessary functionality.

Coil Section #4 (1-0027) is shown as a reheat coil. It is shown as a 4row coil, but can be any number of rows deep. In this embodiment, theframe is shown as a standard 6 row frame, but the last two rows have notbeen punched for tubes, and access holes/panels/gaskets/covers have beenincluded to allow equipment such as cleaning wands, sprayers, brushes,lights and cameras to be inserted between the two coil sections to allowobservations to be conducted and maintenance to be performed. It isdepicted as the last coil in the series, so, downstream access is likelyto exist. If needed for the application, openings upstream anddownstream of the coil cold be provided. The coil frame can be any size,as long as there is adequate room for cleaning, flushing, observationand maintenance duties to be performed through openings in each side ofthe coil frame. If there were not access holes/panels/gaskets/coversupstream from this coil, the frame could be a standard frame, withaccess holes/panels/gaskets/covers located upstream or downstream fromthe 2 row active coil section.

FIG. 26A is a depiction of an AHU coil configuration that includes a tworow (2R) Pre Heat Coil (PHC) that is 3″ deep, a 22″ wide access baybetween the coil casings, a first six row (6R) Cooling Coil (CC #1) thatis 9″ deep, a 22″ wide access bay between the coil casings, a second sixrow (6R) Cooling Coil (CC #2) that is 9″ deep, a 22″ wide access baybetween the coil casings, a six row (6R) Cooling Recovery Coil (CRC)that is 9″ deep, a 22″ wide access bay between the coil casings, and afour row (4R) Re-Heat Coil (RHC) that is 6″ deep, and has a total coilsection length of 124″. Using two six (6) row cooling coils instead of asingle 10 row or 12 row coil is fairly typical in hospital typeenvironments, as it is easier to reach and clean the middle of a 6 rowcoil vs. being able to reach the middle of a 10 or 12 row coil.

FIG. 26B is a material optimized, resource efficient, coil bank layoutthat still allows the front and back of each of the coil sections to beaccessed and cleaned. The same heat transfer row counts are included inthe CC2A configuration as are in the CC2 configuration. Variations ofthe 1-0026, 1-0015, 1-0030 and 1-0027 coils are included in thisdepiction, with added coils.

In this depiction, the PHC 1-0026 and CC #1 1-0015 are combined into onecoil bank assembly that includes a two row (2R) wide access sectionbetween the two coils, with removable plates shown as squares. CC #21-0015A and the CRC 1-0030 coil bank assemblies includes six row (6R)coils with a two row (2R) wide access section shown at the entrance toeach of the coils, with removable plates shown as squares. The RHC1-0027 coil bank assembly includes a four row (4R) coil with a two row(2R) wide access section shown at the entrance to the coils, withremovable plates shown as squares.

The access sections can be wider or narrower than depicted in thediagram, typical for all depictions. Coils and access panels andopenings can be combined in a variety of ways as may be needed forconstructability or performance issues.

The inlet side of the PHC 1-0026 may be available for cleaning, byremoving the air filters from their frames. The downstream side of thePHC 1-0026 can be available for cleaning by opening up the access panelson the downstream side of the PHC 1-0026 coil. The inlet side of the CC#1 1-0015 is accessed from the same openings that serve the dischargeside of the PHC1-0026. The downstream side of the CC #1 1-0015 isavailable for cleaning by opening up the access panels on the downstreamside of the coil, shown as being installed on the CC #2 1-0015A inletside in this depiction.

The inlet side of the CC #2 1-0015A is accessed from the same openingsthat serve the discharge side of CC #1 1-0015. The downstream side ofthe CC #2 1-0015A is available for cleaning by opening up the accesspanels on the downstream side of the coil, shown as being installed onthe CRC 1-0030 inlet side in this depiction. The inlet side of the CRC1-012 is accessed from the same openings that serve the discharge sideof the CC #2 1-0015A. The downstream side of the CRC 1-0030 is availablefor cleaning by opening up the access panels on the downstream side ofthe coil, shown as being installed on the RHC 1-0027 inlet side in thisdepiction. The inlet side of the RHC 1-0027 is accessed from the sameopenings that serve the discharge side of the CRC 1-0030. The downstreamside of the RHC 1-0027 can either be accessed from the AHU dischargeplenum, or by installing a RHC 1-0027 that is equipped with the accesspanels on the inlet and discharge sides of the RHC 1-0027. Theconfiguration shown in FIG. 26B has a total coil section length of 48″,reducing the length of the coil section by 76″, or 61%.

FIG. 27A is a depiction of an AHU coil configuration that includes a tworow (2R) Pre Heat Coil (PHC) 1-0026 that is 3″ deep, a 22″ wide accessbay between the coil casings, a first six row (6R) Cooling Coil (C/C #1)1-0015 that is 9″ deep, a 22″ wide access bay between the coil casings,a second six row (6R) Cooling Coil (C/C #2) 1-0015A that is 9″ deep, a22″ wide access bay between the coil casings, a first six row (6R)Cooling Recovery Coil (CRC #1) 1-0030 that is 9″ deep, a 22″ wide accessbay between the coil casings, a second six row (6R) Cooling RecoveryCoil (CRC #2) 1-0033 that is 9″ deep, a 22″ wide access bay between thecoil casings, a four row (4R) Re-Heat Coil (RHC) 1-0027 that is 6″ deep,and has a total coil section length of 155″.

Using two six (6) row cooling coils instead of a single 10 row or 12 rowcoil, such as in hospital type environments, is easier to reach andclean the middle of a 6 row coil vs. being able to reach the middle of a10 or 12 row coil.

FIG. 27B is a material optimized, resource efficient, coil bank layoutthat still allows the front and back of each of the coil sections to beaccessed and cleaned. The same heat transfer row counts are included inthe FIG. 27B configuration as are in the FIG. 27A configuration.Variations of the 1-0026, 1-0015, 1-0030 and 1-0027 coils are includedin this depiction, with added coils.

In this depiction, the PHC 1-0026 and C/C #1 1-0015 are combined intoone coil bank assembly that is equipped with a two row (2R) wide accesssection between the two coils, and an additional two row (2R) wideaccess section downstream from C/C #1, with removable plates shown assquares. C/C #2 1-0015A and the CRC #1 1-0030 are combined into one coilbank assembly that is equipped with a two row (2R) wide access sectionbetween the two coils, with removable plates shown as squares. CRC #21-0033 and the RHC 1-0027 are combined into one coil bank assembly thatis equipped with a two row (2R) wide access section upstream from CRC #2and an additional two row (2R) wide access section between the twocoils, with removable plates shown as squares. The access sections canbe wider or narrower than depicted in the diagram, typical for alldepictions. Coils and access panels and openings can be combined in avariety of ways as may be needed for constructability or performanceissues.

The inlet side of the PHC is available for cleaning, typically byremoving the air filters from their frames. The downstream side of thePHC is available for cleaning by opening up the access panels on thedownstream side of the PHC coil.

The inlet side of the C/C #1 1-0015 is accessed from the same openingsthat serve the discharge side of the PHC 1-0026. The downstream side ofthe C/C #1 1-0015 is available for cleaning by opening up the accesspanels on the downstream side of the coil, shown as being installed onthe C/C #2 1-0015A inlet side in this depiction.

The inlet side of the C/C #2 1-0015A is accessed from the same openingsthat serve the discharge side of C/C #1 1-0015. The downstream side ofthe C/C #2 1-0015A is available for cleaning by opening up the accesspanels on the downstream side of the coil, shown as being installed onthe CRC #1 1-0030 inlet side in this depiction.

The downstream side of the CRC #1 1-0030 is available for cleaning byopening up the access panels on the downstream side of the coil, shownas being installed on the CRC #2 1-0033 inlet side in this depiction.The inlet side of the CRC #2 1-0033 is accessed from the same openingsthat serve the discharge side of the CRC #1 1-0030. The downstream sideof the CRC #2 1-0033 is available for cleaning by opening up the accesspanels on the downstream side of the CRC #2 1-0033 coil, shown as beinginstalled on the RHC inlet side in this depiction.

The inlet side of the RHC 1-0027 is accessed from the same openings thatserve the discharge side of the CRC #2 1-0033. The downstream side ofthe RHC 1-0027 can either be accessed from the AHU discharge plenum, orby installing a RHC 1-0027 that is equipped with the access panels onthe inlet and discharge sides of the RHC 1-0027. This configuration hasa total coil section length of 60″, reducing the length of the coilsection by 95″.

FIG. 28A is a depiction of an AHU coil configuration that includes a tworow (2R) Pre Heat Coil (PHC) 1-0026 that is 3″ deep, a 22″ wide accessbay between the coil casings, a first six row (6R) Cooling Coil (C/C #1)1-0015 that is 9″ deep, a 22″ wide access bay between the coil casings,a second six row (6R) Cooling Coil (C/C #2) 1-0015A that is 9″ deep, a22″ wide access bay between the coil casings, a first four row (4R)Cooling Recovery Coil (CRC #1) 1-0030 that is 6″ deep, a 22″ wide accessbay between the coil casings, a second two row (2R) Cooling RecoveryCoil (CRC #2) 1-0033 that is 3″ deep, a 22″ wide access bay between thecoil casings, a four row (4R) Re-Heat Coil (RHC) 1-0027 that is 6″ deep,and has a total coil section length of 146″. Using two six (6) rowcooling coils instead of a single 10 row or 12 row coil can be used inhospital type environments, as it is easier to reach and clean themiddle of a 6 row coil vs. being able to reach the middle of a 10 or 12row coil.

FIG. 28B is a material optimized, resource efficient, coil bank layoutthat still allows the front and back of each of the coil sections to beaccessed and cleaned. The same heat transfer row counts are included inthe FIG. 28B configuration as are in the FIG. 28A configuration.Variations of the 1-0026, 1-0015, 1-0030 and 1-0027 coils are includedin this depiction, with added coils.

In this depiction, the PHC 1-0026 is equipped with a two row (2R) wideaccess section, with removable plates shown as squares. The accesssection can be wider or narrower than depicted in the diagram (and eachof the other depictions)

C/C #1 1-0015 and C/C #2 1-0015A are combined into one coil bankassembly that includes a two row (2R) wide access section between thetwo coils, with removable plates shown as squares. CRC #1 1-0030 and theCRC #2 1-0033 are combined into one coil bank assembly that includeswith a two row (2R) wide access section shown to be upstream from CRC #11-0030, with an additional two row (2R) wide access section between thetwo coils, with removable plates shown as squares. The RHC 1-0027 coilbank assembly includes a four row (4R) coil with a two row (2R) wideaccess section shown at the entrance to the coil, with removable platesshown as squares. The access sections can be wider or narrower thandepicted in the diagram. Coils and access panels and openings can becombined in a variety of ways as may be needed for constructability orperformance issues.

The inlet side of the PHC 1-0026 is available for cleaning, typically byremoving the air filters from their frames. The downstream side of thePHC 1-0026 is available for cleaning by opening up the access panels onthe downstream side of the PHC 1-0026 coil. The inlet side of the C/C #11-0015 is accessed from the same openings that serve the discharge sideof the PHC 1-0026. The downstream side of the C/C #1 1-0015 is availablefor cleaning by opening up the access panels on the downstream side ofthe coil, shown as being installed between the C/C #1 1-0015 and the C/C#2 1-0015A in this depiction.

The inlet side of the C/C #2 1-0015A is accessed from the same openingsthat serve the discharge side of C/C #1 1-0015. The downstream side ofthe C/C #2 1-0015A is available for cleaning by opening up the accesspanels on the downstream side of the coil, shown as being installed onthe CRC #1 1-0030 inlet side in this depiction. The downstream side ofthe CRC #1 1-0030 is available for cleaning by opening up the accesspanels on the downstream side of the coil, shown as being installedbetween the CRC #1 1-0030 and the CRC #2 1-0033 in this depiction.

The inlet side of the CRC #2 1-0033 is accessed from the same openingsthat serve the discharge side of the CRC #1 1-0030. The downstream sideof the CRC #2 1-0033 is available for cleaning by opening up the accesspanels on the downstream side of the CRC #2 1-0033 coil, shown as beinginstalled on the RHC 1-0027 inlet side in this depiction.

The inlet side of the RHC 1-0027 is accessed from the same openings thatserve the discharge side of the CRC #2 1-0033. The downstream side ofthe RHC 1-0027 can either be accessed from the AHU discharge plenum, orby installing an RHC 1-0027 that is equipped with the access panels onthe inlet and discharge sides of the RHC 1-0027. This configuration hasa total coil section length of 51″, reducing the length of the coilsection by 95″, or 65%.

FIGS. 29-31 illustrate improved systems for distributing cleaning andflushing agents into a coil system (e.g., including any of the coilsdescribed herein, such as the PHC 1-0026, CC 1-0015, second CC 1-0015A,CRC 1-0030, second CRC 1-0033, and RHC 1-0027) consistent withimplementations of the current subject matter. As shown in FIGS. 29-31,5001 is a hose connection into the longitudinal member of the top frame.It is shown on the upstream side of the longitudinal member of the topframe, but it can be connected into the downstream member of the topframe, or the short sides of the frame as well, if interconnection holesare provided to allow fluid transfer to occur between the frame members.The hose connection can be supported within the unit, or connected tothe exterior of the unit to enhance ease of use. A shut off valve orplug is provided to reduce treated air escaping from the unit when thefan is operational.

5002 are slots or holes in the coil casing/frame pointed inward towardsthe center of the coil. These holes are placed as needed and extend forthe length of the coil casing/frame. These holes allow properdistribution of the cleaning/disinfecting/flushing agents to occur alongthe entire length of the coil. They may be placed low in the frame toreduce trapping any fluids inside the frame.

The term “slots or holes” is generic for openings in the coil casing orsheet metal as designed to allow cleaning/disinfecting/flushing agentsto enter and be distributed throughout the heat transfer coil fin pack.The “slots or holes” can be of any shape or size and location to be usedto evenly distribute fluids across the top of the finned surface area.

5003 are slots or holes in the top sheet metal that is in rough contactwith the top of the heat transfer finned surface area, that allowcleaning/disinfecting/flushing agents to be spread evenly across thecoil heat transfer surface area, from the top of the coil section, beinggravity fed, or pressure fed from within the cavity formed by thecasings/frames, and the sheet metal/aluminum etc. that is enclosing thatspace. Slots are positioned and sized to minimize air bypass around theheat transfer surface.

5004 are small diameter holes or slots in the bottom of thecasing/frame/header as required to drain thecleaning/disinfecting/flushing agents from that space to prevent fluidsbeing trapped within that cavity.

5005 are openings, blanks off plates, screws, attaching systems,gaskets, reinforcements, as required to be able to insert cameras,lights, cleaning and spraying tools between the coil banks or betweenrows of coils contained in a single coil bank, to facilitateobservation, cleaning, disinfecting and maintenance of the heat transfersurface areas.

5006 are staggered heat transfer tube arrangements in heating, coolingand dehumidification heat transfer applications.

5007 illustrate locations where heat transfer tubes would be located,and are shown for reference only. In the illustrated configurations, thetubes and holes would not be located at the locations 1-5007.

5008 is a heat transfer coil section. Multiple coil sections are shownin some embodiments.

5009 is a top plate, used to enclose the area where thecleaning/disinfecting/flushing agents may be injected into the system.The top plate 5009 may be welded or otherwise fastened and sealed toallow the area to be pressurized, and to prevent air bypass or fluidleakage from this area. It is only shown in one location, but can beused for all embodiments using this methodology.

1-0026 is depicted as a PHC as described previously herein, but the heattransfer surface can be used for a variety of applications, includingenergy reclaimed from various sources, among others. Greater or lesseramount of rows can be used in this application and this location.

1-0015 is depicted as a CC (e.g., CC 1-0015) as described previouslyherein, but the heat transfer surface can be used for a variety ofapplications. Greater or lesser amount of rows can be used in thisapplication and this location.

1-0030 is depicted as an energy recovery coil (ERC) or Cooling RecoveryCoil (CRC), (e.g., CRC 1-0030) as described previously herein, but theheat transfer surface can be used for a variety of applications. Greateror lesser amount of rows can be used in this application and thislocation.

1-0027 is depicted as a RHC as described previously herein, but the heattransfer surface can be used for a variety of applications. Greater orlesser amount of rows can be used in this application and this location.

1-5014 is a sealing plate and gasketing system between the various coilbanks to prevent air bypass and leakage between the various coilsections and the AHU. It is only shown in one place but may be appliedas needed between all coil sections and AHU structure.

1-5015 is the coil casing/frame, typical for each coil section.

1-5016 are sealable openings where maintenance and observation equipmentcan be inserted.

FIGS. 32-36 illustrate various coil configurations consistent withimplementations of the current subject matter. For example, FIGS. 32-36depict variations of the easy to clean coil configurations, with theadded abilities to remove or add fluid at different temperatures fordifferent uses from the coil bank, and controlling the number of activerows to control the amount of sensible vs. latent heat being removedfrom, or added to the airstream. Many of the details depicted in theprevious figures are omitted from these figures for clarity, but may beincluded in the described configurations herein.

In some applications, cool water, above the area dewpoint temperature,may need to be generated by these embodiments to serve radiant coolingsystems, induction units, passive or active chilled beams, equipment orprocess cooling loads and other systems that need to avoid condensationat the unit, in the spaces or in the equipment/process.

In many cases, a completely separate cooling system, including low liftchillers, cooling towers, and distribution piping and pumping systems isincorporated into the facility to provide this cool water at significantadded expense. Existing Cooling Coil (CC) and Air Handling Unit (AHU)designs do not provide the ability for partially warmed up water to bepulled from the cooling coil and used for other purposes, such as theuses described above. Significantly reduced equipment costs and energyuse can be derived from implementation of the various embodiments.

In some embodiments of the current subject matter, control valves can beutilized to control the flow through, or eliminate the flow fromindividual coil sections to change the average fluid temperature withinthe coil, or at the coil finned heat transfer surface area by varyingthe amount of active heat transfer surface area to change the ratio ofthe sensible to latent capacity of the coil bank.

In some embodiments, control strategies for coil-based Thermal EnergyStorage (TES) are incorporated to allow the cooling system to shut down,or significantly reduce the capacity being delivered from therefrigeration equipment. This can be especially effective during lightload hours.

For DX based systems, refrigerant receiver thanks and refrigerant pumpsmay be utilized to help improve this process.

As shown in FIGS. 32-36, 5500 is a header where heat transfer fluid iseither injected into, or withdrawn from a heat transfer coil system.5501, 5502, and 5503 are also headers where heat transfer fluid iseither injected into, or withdrawn from a heat transfer coil system.5504, 5505, 5506, and 5507 are points of connection between heating orcooling systems and various heat transfer coil sections or systems.5524, 5525, and 5526 are shown as control valve systems to control theflow of fluids into or out of the heat transfer coil sections orsystems. 5534, 5535, and 5536 are shown as piping systems to allowtransportation of the flow of fluids into or out of the heat transfercoil sections or systems.

Condensate Management

As noted above, common problems created by industry standard coolingcoil, cooling unit, cooling systems and HVAC designs include, but arenot limited to: high airside pressure drop; excessive cooling coilvertical height that creates a condensate “stacking” effect; inadequatenumbers of coil rows can create a condensate stacking effect; inadequateand poorly designed cooling coil drain pans; excessive air velocityacross the coil sections during deep dehumidification duties; excessiveliquid water (condensate) being carried off of the coil into the unitand downstream ductwork; and condensate carry-off being re-evaporatedinto the airstream; condensate being carried off and re-evaporated offof the cooling coil and drain pan systems due to compressor cycling onand off; condensate being carried off and re-evaporated off of thecooling coil and drain pan systems due to temperature swings; inabilityto unload far enough to provide proper temperature and RH control whenloads are light; energy waste, excessive water and chemical consumption;excessive energy rejection to, or withdrawal from, ground coupled HVACsystems; undersized ductwork and air distribution terminal units; andother common system design and operational problems. Implementations ofcondensate management systems described herein may help to solve one ormore of these problems.

Generally, air conditioning cooling coils designed into most HVACsystems have been optimized to remove dry heat from the airstream, withdehumidification (moisture removal) being a byproduct of creating coldair. When a cooling coil cools air down below the “dewpoint” of the air,water vapor condenses on the cooling coil and forms what is called“condensate”. With existing coil designs being optimized for dry heatremoval, not moisture removal, a significant problem is created. In manycases, condensate can be generated by a cooling coil faster than thecondensate can be drained out of the coil, due to the coil and heattransfer fin designs. Unfortunately, the condensate that remains in thecooling coil can significantly impede the heat transfer process. Forexample, condensate may not be removed from the coil heat transfer finsfor much of the height of the coils, creating a condition calledcondensate stacking. When condensate stacking occurs, a significantportion of the cooling coil heat transfer finned surface area is filledwith condensate. This can reduce the airflow, or completely stop theairflow through that section of the coil. When this occurs, significantother problems, such as chiller plant “Low Delta T Syndrome” andcondensate being blown off the coil into the AHU and downstream ductworkcan occur, wasting energy and creating conditions that can promotebiological growth and systems/equipment corrosion, with all of theattendant problems.

Note that these condensate management heat transfer coil designs areindependent of the fluid or vapor contained within the coil tubing andflowing over and around the coil tubing and heat transfer fin systems.It should also be noted that the condensate management fin variationsdescribed herein can be combined in various ways. For example, theconfiguration shown in FIG. 40 (e.g., dimpling), FIG. 41 (e.g.,channeling), FIG. 42 (e.g., shaped fin extensions), FIG. 45 (e.g.,variable length fin extensions), and FIG. 64 (e.g., condensate recoverysystem) can all be combined into one heat transfer system to rapidlyremove condensate from a coil and promote more effective heat transferbetween the coil and the airstream or other media passing over the heattransfer surface area. Note that variations of the type of fan andlocation of the fan are included, but not shown. Note that for allvariations that show pre-heat coils (PHCs), Cooling Recovery Coils(CRCs), or reheat coils, (RHCs), pre-heat coils (PHCs), Cooling RecoveryCoils (CRCs), or reheat coils may not actually be required by theprocess or end use needs, and for variations that do not show pre-heatcoils (PHCs), Cooling Recovery Coils (CRCs), or reheat coils, they mayactually be required by the process or end use need.

The various designs that include horizontal and angled coilarrangements, or enhanced fin arrangements that drop the condensate offof the coils and fins into the supply airstream have the benefit ofbeing designed specifically for additional dehumidification andadditional energy recovery. The condensate leaving the heat transferfinned surfaces can be very close to the temperature of the heattransfer finned surfaces, which can be several degrees below the airtemperature leaving the cooling coil (C/C). This is especially true whenthe enhanced and extended finned surfaces are present. Normally, withoutthe use of some form of energy recovery from the condensate system, thisvery cold water is sent down the drain, carrying with it a significantamount of cooling energy. With these condensate management designs, thevery cold water droplets in the airstream are in contact with the supplyair for a period of time, during their decent through the supplyairstream and added time while the water is in the drain pans, flowingtowards the condensate drain, on the path out of the AHU. Since thecondensate droplets are at a lower temperature than the dewpointtemperature of the air, the water droplets actually condense moremoisture out of the supply airstream, further drying the air out. Energyis transferred out of the airstream into the condensate, so less BTU'sare sent out of the AHU in the form of cold condensate.

FIGS. 37-50 illustrate various coil fin configurations consistent withimplementations of the current subject matter, that may be implementedin any of the coil configurations described herein (e.g., the PHC1-0026, the CC 1-0015, the second CC 1-0015A, the CRC 1-0030, the secondCRC 1-0033, and the RHC 1-0027, etc.).

FIG. 37 illustrates horizontal cooling coil fins having flat bottomedges, which makes it more difficult for condensate being generated bythe cooling coil system to gain enough mass to form a drip, and to drainfrom the heat transfer surface area. Draining condensate from the coilfins enhances the heat transfer ability. FIG. 37 depicts one form of acoil fin designed specifically to focus the condensate into a point,which will allow the coil to drain more rapidly and effectively. Atriangle shape, located between the coil tubes is shown. A rounded finextension, as opposed to a triangular fin extension, could be used aswell, to reduce the potential for the tip to be broken or bent easily.Other shapes, sizes and locations may be utilized for the fin extensionsas well.

As shown in FIG. 38 , many cooling coils are installed in a positionthat is neither horizontal, nor vertical. As with the horizontallymounted coils, these coils typically have flat edges, with no focalpoint for the condensate. This makes it more difficult for condensatebeing generated by the cooling coil system to gain enough mass to form adrip, and to drain from the heat transfer surface area. Drainingcondensate from the coil fins enhances the heat transfer ability. FIG.38 depicts one form of a coil fin designed specifically to focus thecondensate into a point, which will allow the coil to drain more rapidlyand effectively. A triangle shape, located between the coil tubes isshown. This depiction shows the point of the fin extension pointeddirectly down. Other shapes, such as the shape depicted in FIG. 37 ,sizes and locations may be utilized for the fin extensions as well.

FIG. 39 is another variation of FIG. 37 , with the coil depicted asbeing installed in a non-horizontal fashion.

FIG. 40 depicts the finned surface, as well as the extended finsurfaces, as having dimpled surfaces, along the lines of a golf ball.Dimpled surfaces reduce air pressure drop, and increase heat transfereffectiveness as well. FIG. 40 can be applied to any of the coilconfigurations described herein.

FIG. 41 shows a version of FIGS. 37-47, 49, and 50 with the extendedsurface having channels (e.g., slight indentations), which guide thecondensate to the tip of the extended fin surface for more rapidcondensate removal. For the FIG. 38 variant, or other non-horizontalversions, the channels would be configured differently, with thechannels configured in a manner that guides the condensate to the tip,or other drip-point, of the extended fin surfaces. This configurationcan also be utilized in coils that do not have the extended fin surface,the channels would focus the condensate in a manner that promotes morerapid condensate removal.

FIG. 42 shows a variation of the extended fin surface area for a coilwith airflow moving in a horizontal, or near horizontal direction. Inthis variation, there are significant fin extensions shown. Thecondensate will tend to drip from the higher fin extensions to the lowerfin extensions, rather than be trapped in the main body of the coil,where it will impede heat transfer. As with the other variations, FIG.42 can be built with dimpled, or channeled, or both, fin enhancements.

FIG. 43 is a variation of FIG. 42 . This variation includes longer finextensions on the upper coil rows than on the lower coil rows. In thisvariation, rather than the condensate from the upper row fin extensionsdripping onto the lower row fin extensions, the upper row fin extensionsare slightly longer than the lower fin extensions, such that condensatethat drips off of the upper fin extensions does not come in contact withthe lower fin extensions, promoting more rapid condensate removal, andthus more active and effective heat transfer surface area.

This same effect can be obtained by installing one of the other coilconfiguration variations in a slightly off of vertical orientation, withthe angle of the coil being such that condensate dripping from the upperrows extended fin surface will not hit the fin extensions on the lowerrows, so condensate will be removed from the heat transfer surface areamore rapidly, again promoting more active and effective heat transfersurface area.

In FIG. 44 , every other fin is extended slightly longer than the fin oneither side of it. The slightly longer length is adequate to reduce theair pressure drop associated with this design. The extended fin surfaceis equipped with an angle that would tend to accumulate condensate andform it into a “river” flowing down the “inside” of the angle. Water isattracted to water, so this continually flowing stream of condensatewill tend to attract condensate from the fin directly adjacent to it, onthe inside of the angle. Condensate from the one side of the finadjacent to the extended surface fin will tend to be attracted to thelonger fin as well, on the “outside” of the angle, as there may becondensate bridging between the fin surfaces.

FIG. 45 is a variation of FIG. 44 that does not have the angle builtinto the longer extended fin surface. The function is similar, in thatthe condensate will tend to accumulate on both sides of the extended finsurface between the two shorter length fin surfaces. Condensate willdrain more rapidly from a coil, when it is concentrated and is not“sandwiched” between two fins. The condensate will tend to leave theshorter fins, and be attracted to the longer fins, and be pushed by theair flowing through the coil to the “downwind” side of the longer heattransfer fin, out and away from the body of the coil, enhancing the heattransfer coil effectiveness.

FIG. 46 is a variation of FIG. 45 , with the coil mounted horizontally.The horizontal nature of the fins enhances the drainage from theextended fin surfaces.

FIG. 47 is a variation of FIG. 37 and FIG. 42 . The configuration inFIG. 47 is depicted with a horizontal coil configuration, but verticaland slanted coil orientations will function in a similar manner. Withthis variation, there are no “flat spots” on the extended finsurfaces—the entire leaving edge of the heat transfer fin is a shapedfin. With this variation, the shortest length of the extended fin islocated closest to the heat transfer tubing, where the air velocity isthe lowest. Because the air velocity is greatest between the tube-rows,the longest part of the extended fin surface will be exposed to thehighest velocity air, so the air contact time across the shaped finsurface will tend to be equalized, enhancing heat transfereffectiveness.

FIG. 48 is a variation of FIG. 47 . FIG. 48 shows a different finorientation that may be required to optimize condensate management fordifferent coil orientations (vertical, sloped, horizontal) and differentair velocities and entering and leaving conditions. When air velocitiesare low, the low pressure area on the leaving side of the heat transfertubing will tend to draw condensate into that low pressure zone. On lowair velocity coils, the shortest length of the extended fin may belocated somewhere between the coils in order to take advantage of thisnature. The installation angle of the coils may contribute todetermining where the “short” length of the extended fin will belocated.

FIG. 49 is a variation of the extended fin surface shape, shown forreference. In the diagram, it is depicted as having vertically downairflow, although the coil orientation can be vertical, or any angle inbetween as well. There are a multitude of extended fin surface shapesthat can be utilized effectively, that will depend on fluid velocitiesand fluid characteristics flowing across and through the coil, and thedesired leaving fluid conditions, as well as the characteristics of thefluids contained within the heat transfer tubing.

FIG. 50 is similar to FIG. 49 and shows a variation of the extended finsurface, with the coil shown being installed at an angle.

FIGS. 51-64 illustrate various condensate management air handling unitconfigurations consistent with implementations of the current subjectmatter, the can be implemented with any of the components of the AHUsdescribed herein (e.g., the PHC 1-0026, the CC 1-0015, the second CC1-0015A the CRC 1-0030, the second CRC 1-0033, and the RHC 1-0027,etc.).

FIG. 51 is one depiction of a condensate management designed AirHandling Unit (AHU) equipped with a “Cooling Recovery Coil” (CRC)1-0030. The AHU may include pre- and post-AHU air filtration systems1-0100, pre-heat coils 1-0026, reheat coils 1-0027, humidificationsystems, UGVI 1-0031, PCO 1-0032, mist eliminators, drain pans and thelike, which are not shown for clarity. This condensate management AHU isshown with a pair of variable speed ECM driven plug fans pushing aconstant or variable volume of air through a cooling coil (e.g., CC1-0015 as described herein), with the cooling coil shown to be equippedwith extended heat transfer fins for enhanced condensate management. Thecooling coil can be a large, low air velocity coil as needed to meet theneeds of the end use and also provide adequate heat quality (a highenough chilled water return temperature) in the chilled water returnstream leaving the cooling coil to meet the needs of the CRC (e.g., CRC1-0030 as described herein) for the control of relative humidity andtemperature in the conditioned spaces or process loads. In thisdepiction, the Cooling Coil (C/C) is shown to be installed at an angle,to reduce the overall size of the AHU, and the CRC is shown as a smallercross sectional coil, with higher air velocities to reduce AHUconstruction costs and mesh with potential space restrictions that maybe present.

FIG. 52 is a variation of FIG. 51 , shown with the C/C mounted in ahorizontal fashion with the air blowing vertically downward through thecooling coil, for maximum condensate removal effectiveness.

FIG. 53 illustrates a horizontally configured, compact, condensatemanagement, CRC-based AHU. The configuration in FIG. 53 is shown withair filters that pull air from three sides of the AHU to keep the airfilter air velocities low, and lowering the vertical height of the AHU.The ECM plug fan(s) is (are) pressurizing a plenum, and a velocitykilling perforated plate is shown between the fan wheel and thePHC—preheat coil. The PHC discharges into a plenum, where a horizontallymounted condensate management C/C is located. Air from the C/C dischargeplenum enters a CRC, where the air is reheated using reclaimed chilledwater return line energy. The CRC discharge plenum sends air into thesystem where a reheat coil or coils may be located for finalconditioning of the air, as may be required.

FIG. 54 is one version of a vertically configured, compact, condensatemanagement, CRC-based AHU. The configuration of FIG. 54 is shown withtwo different sets of air filters in series with one another, and a PHCshown in two potential locations, one, just after the filters, onedownstream from the plug fan(s). The ECM plug fan(s) is (are)pressurizing a plenum, and a velocity killing perforated plate is shownbetween the fan wheel and the PHC—preheat coil alternate location. ThePHC discharges into a plenum, where a vertically mounted condensatemanagement C/C is located. Air from the C/C discharge plenum enters aCRC, where the air is reheated using reclaimed chilled water return lineenergy. The CRC discharge plenum sends air into the system where areheat coil or coils may be located for final conditioning of the air,as may be required.

FIG. 55 is one variation of a vertically configured, compact, condensatemanagement, CRC-based AHU, consistent with implementations of thecurrent subject matter. The configuration of FIG. 55 is shown with twodifferent sets of air filters in series with one another, and a PHCshown in two potential locations, one, just after the filters, onedownstream from the plug fan(s). The ECM plug fan(s) is (are)pressurizing a plenum, and a velocity killing perforated plate is shownbetween the fan wheel and the PHC—preheat coil alternate location. ThePHC discharges into a plenum, which is feeding air into an angle-mountedcondensate management C/C. The condensate management C/C is configuredin such a manner that the coil is still a blow through coil, with theleaving air side of the coil at the lower elevations and the variousforms of condensate management fin designs can enhance condensateremoval from the C/C. Air from the C/C discharge plenum enters avelocity reducing (or eliminating) perforated plate that is shown tohelp equalize the air flow through an angle-mounted CRC, where the airis reheated using reclaimed chilled water return line energy. The CRCdischarge plenum sends air into the system where a reheat coil or coilsmay be located for final conditioning of the air, as may be required.

FIG. 56 is a variation of a compact, condensate management, CRC-basedAHU. The configuration of FIG. 56 is shown with two different sets ofair filters in series with one another, and a PHC shown upstream fromthe fan inlet. The ECM plug fan(s) is (are) pressurizing a plenum, and avelocity killing perforated plate is shown between the fan wheel and anangle-mounted condensate management C/C. The condensate management C/Cis configured in such a manner that the coil is still a blow throughcoil, with the leaving air side of the coil at the lower elevation andthe various forms of condensate management fin designs can enhancecondensate removal from the C/C. Air from the C/C discharge plenumenters a vertically oriented CRC (could be an angle-mounted CRC tofurther reduce the AHU profile) where the air is reheated usingreclaimed chilled water return line energy. The CRC discharge plenumsends air into the system where a reheat coil or coils may be locatedfor final conditioning of the air, as may be required.

FIG. 57 shows a draw through variation of the condensate management AHU,where the fan is pulling (or “drawing”) air through the C/C. Theconfiguration of FIG. 57 is depicted without most of the variousaccessories associated with AHU's for clarity. The condensate managementC/C is shown as a horizontal coil in this depiction, but it can beangled or vertical as well. In this depiction, the C/C discharges airvertically down into the suction plenum of the fan systems. There is avelocity killing perforated plate is shown between the C/C and the misteliminator and the inlet to the fan wheel(s). There may be significantcondensate “raining” down into the fan suction plenum, so misteliminators are shown in the fan suction plenum. The fan is depicteddischarging into a fan discharge plenum, which is also the CRC inletplenum. Air from the fan discharge plenum enters a vertically orientedCRC (could be an angle-mounted CRC to further reduce the AHU profile)where the air is reheated using reclaimed chilled water return lineenergy.

FIG. 58 is a variation of FIG. 57 , in which the vertical CRC is mounteddownstream from the velocity killing perforated plate and the misteliminator, and upstream from the fan inlet plenum. The CRC could beangle-mounted to further reduce the AHU profile.

FIG. 59 is a variation of FIG. 58 , in which a different fan type isbeing depicted.

FIG. 60 illustrates a compact, condensate management, CRC-based AHU. Theconfiguration of FIG. 60 is shown with two different sets of air filtersin series with one another, and a PHC shown upstream from the fan inlet.The ECM plug fan(s) is (are) pressurizing a plenum, and a velocitykilling perforated plate is shown between the fan wheel and anangle-mounted condensate management C/C. The condensate management C/Cis configured in such a manner that the coil is still a blow throughcoil, with the leaving air side of the coil at the lower elevation andthe various forms of condensate management fin designs can enhancecondensate removal from the C/C. A mist eliminator is shown between theC/C and the CRC, this may or may not be required. Air from the C/Cdischarge plenum enters a vertically oriented CRC (could be anangle-mounted CRC to further reduce the AHU profile) where the air isreheated using reclaimed chilled water return line energy. The CRCdischarge plenum sends air into a RHC or into the system where a reheatcoil or coils may be located for final conditioning of the air.

FIG. 61 is another variation of a compact, condensate management,CRC-based AHU. The configuration of FIG. 61 is shown with two differentsets of air filters in series with one another, and a PHC shown upstreamfrom the fan inlet. The ECM plug fan(s) is (are) pressurizing a plenum,which is feeding a horizontally-mounted condensate management C/C. Thecondensate management C/C is configured in such a manner that the coilis still a blow through coil, with the leaving air side of the coil atthe lower elevation and the various forms of condensate management findesigns can enhance condensate removal from the C/C. A velocity killingperforated plate is shown between the C/C and a mist eliminator, whichis also shown between the C/C and the CRC, this may or may not berequired. Air from the C/C discharge plenum enters a vertically orientedCRC (could be an angle-mounted CRC to further reduce the AHU profile)where the air is reheated using reclaimed chilled water return lineenergy. The CRC discharge plenum sends air into the system where areheat coil or coils may be located for final conditioning of the air asmay be required.

FIG. 62 illustrates another version of a compact, condensate management,CRC-based AHU. It is shown with two different sets of air filters inseries with one another, and a PHC shown upstream from the fan inlet.The ECM plug fan(s) is (are) pressurizing a plenum, which is feeding ahorizontally-mounted condensate management C/C. A velocity killingperforated plate is shown between the fan discharge and the condensatemanagement C/C. The condensate management C/C is configured in such amanner that the coil is still a blow through coil, with the leaving airside of the coil at the lower elevation and the various forms ofcondensate management fin designs can enhance condensate removal fromthe C/C. A velocity killing perforated plate is shown between thecondensate management C/C and the mist eliminator that is also shownbetween the C/C and the CRC, this may or may not be required. Air fromthe C/C discharge plenum enters a vertically oriented CRC (could be anangle-mounted CRC to further reduce the AHU profile) where the air isreheated using reclaimed chilled water return line energy. The CRCdischarge plenum sends air into the system where a reheat coil or coilsmay be located for final conditioning of the air as may be required.

FIG. 63 is a variation of a horizontally oriented, low vertical heightcondensate management, CRC-based AHU. The configuration of FIG. 63 isshown with two different sets of air filters in series with one another,and a PHC shown upstream from the fan inlets. The ECM plug fan(s) is(are) pressurizing a plenum, which is feeding a pair ofvertically-mounted condensate management C/Cs, in a staggeredarrangement. The support structure for the upper coil bank is not shownfor clarity. The staggered C/C's can each be 50% to approximately 80% ofthe clear vertical height within the AHU cabinet. Some implementationscan be as high as two (2) 90% tall coil heights, providing an effective180% height C/C. Velocity reducing perforated plates are not shown, butmay be used to equalize the air flow rates through the two coil banks,or to reduce or eliminate high velocity regions across the coil faces.The condensate management C/Cs are configured in such a manner that thecoil is still a blow through coil. As with other designs describedherein, the various forms of condensate management fin designs canenhance condensate removal from the C/Cs. Air from the C/C dischargeplenum enters a vertically oriented CRC (could be an angle-mounted CRCto further reduce the AHU profile) where the air is reheated usingreclaimed chilled water return line energy. The CRC discharge plenumsends air into the system where a reheat coil or coils may be locatedfor final conditioning of the air as may be required.

FIG. 64 is a variation of FIG. 63 that is effective such as where veryhigh condensate removal requirements exist, or where there is the desireto reclaim the condensate for other uses. Natatoriums and indooragriculture HVAC systems for crops such as Cannabis and Hemp, aresamples of high condensate generation uses. Using the configurationshown in FIG. 64 , a condensate recovery system is used to trap thecondensate generated by the C/C or C/Cs. The condensate is gathered intoa condensate recovery tank, located at each individual AHU, or gatheredtogether into one tank from multiple AHU's or C/C systems. In theexample depicted in FIG. 64 , the condensate is being pumped out of thecondensate recovery tank, using a condensate recovery pump that iscontrolled based on the level of fluid in the condensate recovery tank,into the PCC (Condensate Pre-Cool Coil). While in the PCC, thecondensate, which can be at or below the actual supply air temperaturereceives heat from the airstream where the PCC is located. The PCC canbe located remotely from the AHU, or co-located with the AHU, and serveto precondition the fresh air stream, the mixed air stream, the returnair stream as deemed appropriate. For condensate recovery systems thatincorporate a Reverse Osmosis (RO) membrane into the purificationdesign, the ability of the PCC to add heat to the condensate can improvethe ability of the RO membrane to function effectively, as warmer watercan be processed more effectively than cold water.

As mentioned previously, if the design includes one, or more of theconfigurations shown in FIGS. 37-63 that drips condensate into the airstream, additional dehumidification and energy recovery occurs, inaddition to the energy recovery described in FIG. 64 .

The use of UVGI or other methods to kill/disable biological growth isdescribed in various variations and may be used to reduce fouling insidethe PCC if the UV light is directed at the CC and drain pan systems.Insulated piping may be used, as the temperature of the condensate willbe below the dewpoint temperature of the air in many locations.

FIG. 65 is a variation of a condensate management system consistent withimplementations of the current subject matter that utilizes variableheat transfer fin densities for different rows in the heat transfercoils. In the depiction shown, the air to be treated is entering on theleft side of the coil, while the fluid used to remove heat from the air,contained within the coil tubing, enters the coil on the right side andthe two fluid streams cross each other in a counter-flow direction forthe heat exchange process. Rows with tighter (closer) fin spacing willhave a higher fin surface temperature than rows that are built with finsthat are spaced further apart. Rows that have tighter fin spacing havehigher air pressure drops and are less able to condense moisture out ofthe air than rows with wider fin spacing. Rows with tighter fin spacingare better at treating sensible loads than rows with wider fin spacing,since they have more surface area to transfer heat between the air andthe fins. The variation shown starts with tight fin spacing as the airenters the coil to pull sensible heat out of the air more effectively,and as the air is cooled down, and the need for moisture removal isincreased, the fin spacing is widened out to create a more effectivemoisture removal coil. More air will “bypass” the fins as the finspacing is widened out, so less sensible cooling overall will occur.Such configurations may maximize moisture removal, while minimizingsensible cooling loads.

The gaps between the heat transfer fins for the different fin densitiesallow the air pressure drop to equalize between the length and width andheight, as well as allowing condensed moisture to find the leastrestrictive path to the drain pan.

FIG. 66 is a variation of FIG. 65 that uses two separate coil casings tohouse the different fin densities. The coils can be connected together,or separated as may be desired to allow more effective coil cleaning, orto have two sets of UVGI lights installed, one between the two coilbanks, and one downstream from the second coil bank.

FIG. 67 shows an example of variable coil circuiting, consistent withimplementations of the current subject matter, that optimizes heattransfer between the fluid contained inside the heat transfer tubing andthe fluid, typically air, flowing through the finned surface of thecoil. To enhance effectiveness, the approach temperatures need to bemaximized. The best heat transfer efficiency would be if the fluidinside the coil was flowing fast enough that the inlet and outlettemperature were nearly identical. For a chilled water based coolingsystem, this may not be possible. Even using low chilled water systemtemperature differentials to improve the effectiveness at the coilcreates very significant problems for the system—pipe and pump sizes canbecome enormous and costly to build and operate, chiller efficiency canbe very poor and chiller and equipment wear can be accelerated. In thesystem depicted, to optimize dehumidification, the first rows are“double-circuited”, which means that every tube in the first two rows ofcoil are fed directly from the supply header, so the coils and finnedsurfaces are at their coldest temperature. The coil circuiting thentransitions to another circuiting variation, in this case it is shown asfull circuited. This transition can most easily be accomplished by theuse of an intermediate header that changes the number of tubes fedbetween the inlet side of the header and the outlet side of the header.Another transition is shown as being half-circuited, again using aheader to change the number of tubes being fed. The coil circuiting canvary in numerous ways. The transition headers are shown to have pipingconnections to allow partially warmed up fluid to be withdrawn from thecoil and used elsewhere.

FIG. 68 is an example of the coil circuiting consistent withimplementations of the current subject matter, using the same coilcircuiting throughout the coil. It is shown with an intermediate headerthat is used to withdraw partially warmed up fluid from the coil bankfor use elsewhere.

FIG. 69 shows an improved heat transfer fin design consistent withimplementations of the current subject matter that increases the finnedsurface heat transfer area, and has air gaps between each row. The angleof approach between the fins can be varied to create more or less heattransfer area per row. For added surface area to provide more effectivesensible cooling, the entering air side rows can have larger angles, toprovide longer fins. For reduced surface area to provide more effectivelatent (moisture removal) cooling, the leaving air side rows can havenarrower angles, to the point of being perpendicular to the airflow, toprovide shorter fins. The angles between the entering and leaving sidecan have various angles/fin lengths, or the entire coil can haveconsistent angles between the fins as desired. Utilizing coils that havefinned surfaces with angular approaches to the next row of coilsincreases turbulence and heat transfer effectiveness, especially atlower air velocities which can be typical of Variable Air Volume (VAV)air distribution systems.

Although a few embodiments have been described in detail above, othermodifications are possible. Other embodiments may be within the scope ofthe following claims.

Referring to FIG. 24B, FIG. 24B depicts a block diagram illustrating acontrol system 300 consistent with implementations of the currentsubject matter. Referring to FIGS. 1-24A and 25A-69 , the computingsystem 300 can be used to implement control systems for controlling oneor more features of the AHUs and/or any components of the AHUs describedherein.

As shown in FIG. 24B, the control system 300 can include a processor310, a memory 320, a storage device 330, and input/output device 340.The processor 310, the memory 320, the storage device 330, and theinput/output device 340 can be interconnected via a system bus 350. Theprocessor 310 is capable of processing instructions for execution withinthe control system 300. Such executed instructions can implement one ormore components of, for example, the AHUs described herein. In someexample embodiments, the processor 310 can be a single-threadedprocessor. Alternatively, the processor 310 can be a multi-threadedprocessor. The processor 310 is capable of processing instructionsstored in the memory 320 and/or on the storage device 330 to displaygraphical information for a user interface provided via the input/outputdevice 340.

The memory 320 is a computer readable medium such as volatile ornon-volatile that stores information within the control system 300. Thememory 320 can store data structures representing configuration objectdatabases, for example. The storage device 330 is capable of providingpersistent storage for the control system 300. The storage device 330can be a floppy disk device, a hard disk device, an optical disk device,a tape device, a solid-state device, and/or any other suitablepersistent storage means. The input/output device 340 providesinput/output operations for the control system 300. In some exampleembodiments, the input/output device 340 includes a keyboard and/orpointing device. In various implementations, the input/output device 340includes a display unit for displaying graphical user interfaces.

According to some example embodiments, the input/output device 340 canprovide input/output operations for a network device. For example, theinput/output device 340 can include Ethernet ports or other networkingports to communicate with one or more wired and/or wireless networks(e.g., a local area network (LAN), a wide area network (WAN), theInternet).

In some example embodiments, the control system 300 can be used toexecute various interactive computer software applications that can beused for organization, analysis and/or storage of data in variousformats. Alternatively, the control system 300 can be used to executeany type of software applications. These applications can be used toperform various functionalities, e.g., planning functionalities (e.g.,generating, managing, editing of spreadsheet documents, word processingdocuments, and/or any other objects, etc.), computing functionalities,communications functionalities, etc. The applications can includevarious add-in functionalities or can be standalone computing productsand/or functionalities. Upon activation within the applications, thefunctionalities can be used to generate the user interface provided viathe input/output device 340. The user interface can be generated andpresented to a user by the control system 300 (e.g., on a computerscreen monitor, etc.).

One or more aspects or features of the subject matter described hereincan be realized in digital electronic circuitry, integrated circuitry,specially designed ASICs, field programmable gate arrays (FPGAs)computer hardware, firmware, software, and/or combinations thereof.These various aspects or features can include implementation in one ormore computer programs that are executable and/or interpretable on aprogrammable system including at least one programmable processor, whichcan be special or general purpose, coupled to receive data andinstructions from, and to transmit data and instructions to, a storagesystem, at least one input device, and at least one output device. Theprogrammable system or computing system may include clients and servers.A client and server are generally remote from each other and typicallyinteract through a communication network. The relationship of client andserver arises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

These computer programs, which can also be referred to as programs,software, software applications, applications, components, or code,include machine instructions for a programmable processor, and can beimplemented in a high-level procedural and/or object-orientedprogramming language, and/or in assembly/machine language. As usedherein, the term “machine-readable medium” refers to any computerprogram product, apparatus and/or device, such as for example magneticdiscs, optical disks, memory, and Programmable Logic Devices (PLDs),used to provide machine instructions and/or data to a programmableprocessor, including a machine-readable medium that receives machineinstructions as a machine-readable signal. The term “machine-readablesignal” refers to any signal used to provide machine instructions and/ordata to a programmable processor. The machine-readable medium can storesuch machine instructions non-transitorily, such as for example as woulda non-transient solid-state memory or a magnetic hard drive or anyequivalent storage medium. The machine-readable medium can alternativelyor additionally store such machine instructions in a transient manner,such as for example, as would a processor cache or other random accessmemory associated with one or more physical processor cores.

To provide for interaction with a user, one or more aspects or featuresof the subject matter described herein can be implemented on a computerhaving a display device, such as for example a cathode ray tube (CRT) ora liquid crystal display (LCD) or a light emitting diode (LED) monitorfor displaying information to the user and a keyboard and a pointingdevice, such as for example a mouse or a trackball, by which the usermay provide input to the computer. Other kinds of devices can be used toprovide for interaction with a user as well. For example, feedbackprovided to the user can be any form of sensory feedback, such as forexample visual feedback, auditory feedback, or tactile feedback; andinput from the user may be received in any form, including acoustic,speech, or tactile input. Other possible input devices include touchscreens or other touch-sensitive devices such as single or multi-pointresistive or capacitive track pads, voice recognition hardware andsoftware, optical scanners, optical pointers, digital image capturedevices and associated interpretation software, and the like.

In the descriptions above and in the claims, phrases such as “at leastone of” or “one or more of” may occur followed by a conjunctive list ofelements or features. The term “and/or” may also occur in a list of twoor more elements or features. Unless otherwise implicitly or explicitlycontradicted by the context in which it used, such a phrase is intendedto mean any of the listed elements or features individually or any ofthe recited elements or features in combination with any of the otherrecited elements or features. For example, the phrases “at least one ofA and B;” “one or more of A and B;” and “A and/or B” are each intendedto mean “A alone, B alone, or A and B together.” A similarinterpretation is also intended for lists including three or more items.For example, the phrases “at least one of A, B, and C;” “one or more ofA, B, and C;” and “A, B, and/or C” are each intended to mean “A alone, Balone, C alone, A and B together, A and C together, B and C together, orA and B and C together.” Use of the term “based on,” above and in theclaims is intended to mean, “based at least in part on,” such that anunrecited feature or element is also permissible.

The subject matter described herein can be embodied in systems,apparatus, methods, and/or articles depending on the desiredconfiguration. The implementations set forth in the foregoingdescription do not represent all implementations consistent with thesubject matter described herein. Instead, they are merely some examplesconsistent with aspects related to the described subject matter.Although a few variations have been described in detail above, othermodifications or additions are possible. In particular, further featuresand/or variations can be provided in addition to those set forth herein.For example, the implementations described above can be directed tovarious combinations and subcombinations of the disclosed featuresand/or combinations and subcombinations of several further featuresdisclosed above. In addition, the logic flows depicted in theaccompanying figures and/or described herein do not necessarily requirethe particular order shown, or sequential order, to achieve desirableresults. Other implementations may be within the scope of the followingclaims.

FIGS. 1 through 20, 51 through 64 and 66 depict heat transfer coilsseparate from one another for clarity, and for inclusion of non-coilcomponents in the figures. One skilled in the art would understand thatsome of these coils could be constructed with the cleaning enhancementsand size reductions depicted in FIGS. 25B, 26B, 27B and 28B.

1. A high efficiency dehumidification system for an air handling unit(AHU), the system comprising: a cooling coil including an inlet toreceive chilled liquid at a first temperature from a cooling plant tocool and dehumidify air that passes over the cooling coil, and includingan outlet to output spent chilled liquid at a second temperature, thesecond temperature being greater than the first temperature due to heatexchange from the air to the chilled liquid; a first fluid conduitincluding an input connected with the outlet of the cooling coil, thefirst fluid conduit further including an output junction comprisingfirst and second outputs; a cooling recovery coil including an inletconnected with the first output of the output junction of the firstfluid conduit to receive at least a portion of the spent chilled liquidat about the second temperature, and including an outlet to return thespent chilled liquid from the cooling recovery coil to the coolingplant, a remaining portion of the spent chilled liquid bypassing thecooling recovery coil via the second output of the output junction ofthe first fluid conduit and returning to the cooling plant; a secondfluid conduit including at least one input connected with each of thefirst and second outputs of the output junction, the second fluidconduit further including an outlet to return the spent chilled liquidto the cooling plant; and a control mechanism on the second fluidconduit to control a flow rate of the spent chilled liquid from thecooling recovery coil to the cooling plant, based on at least a dewpointtemperature of the air.
 2. The system of claim 1, wherein the controlmechanism includes a control valve.
 3. The system of claim 1, whereinthe control mechanism includes a variable flow pump.
 4. The system ofclaim 1, further comprising a manual bypass line valve between thesecond output of the first fluid conduit and the input of the secondfluid conduit, to control an amount of the portion and the remainingportion of the spent chilled liquid entering the at least one input ofthe second fluid conduit.
 5. The system of claim 1, further comprising adifferential pressure control valve between the second output of thefirst fluid conduit and the at least one input of the second fluidconduit, to control an amount of the portion and the remaining portionof the spent chilled liquid entering the input of the second fluidconduit.
 6. The system of claim 1, further comprising an automatic flowcontrol valve between the second output of the first fluid conduit andthe at least one input of the second fluid conduit, to control an amountof the portion and the remaining portion of the spent chilled liquidentering the input of the second fluid conduit.
 7. The system of claim1, further comprising a control system to evaluate input datarepresenting one or more variables, and to determine one or more outputsto control the system to control the one or more variables.
 8. Thesystem of claim 1, further comprising a second cooling recovery coilcomprising: an inlet configured to receive at least a portion of thespent chilled liquid from the first cooling recovery coil; and an outletconfigured to return the spent chilled liquid from the second coolingrecovery coil to the cooling plant.
 9. The system of claim 8, furthercomprising a modulating control valve connected with the first andsecond outputs of the output junction, the modulating control valveconfigured to modulate an amount of the spent chilled liquid passingfrom the cooling recovery coil to control a temperature of air thatpasses over the second cooling recovery coil.
 10. The system of claim 1,further comprising a preheat coil for preheating air passing over thepreheat coil to the cooling coil.
 11. The system of claim 1, furthercomprising a reheat coil for controlling a temperature of the airpassing from the cooling recovery coil.
 12. The system of claim 1,further comprising a control system configured to modulate the controlmechanism to control an amount of the portion of the spent chilledliquid entering the cooling recovery coil and an amount of the remainingportion of the spent chilled liquid bypassing the cooling recovery coiland returning to the cooling plant.
 13. A method of operating a highefficiency dehumidification system for an air handling unit (AHU), themethod comprising: receiving, via an inlet of a cooling coil, chilledliquid at a first temperature from a cooling plant to cool anddehumidify air that passes over the cooling coil, transmitting, via anoutlet of the cooling coil through a first fluid conduit, spent chilledliquid at a second temperature, the second temperature being greaterthan the first temperature due to heat exchange from the air to thechilled liquid, wherein the first fluid conduit includes an inputconnected with the outlet of the cooling coil, and wherein the firstfluid conduit further includes an output junction comprising first andsecond outputs; receiving, via an inlet of a cooling recovery coil thatis connected with the first output of the output junction of the firstfluid conduit, at least a portion of the spent chilled liquid at aboutthe second temperature, returning, via an outlet of the cooling recoverycoil, the spent chilled liquid from the cooling recovery coil to thecooling plant, a remaining portion of the spent chilled liquid bypassingthe cooling recovery coil via the second output of the output junctionof the first fluid conduit and returning to the cooling plant; andcontrolling, via a control mechanism connected with a second fluidconduit, a flow rate of the spent chilled liquid from the coolingrecovery coil to the cooling plant, based at least in part on a dewpointtemperature of the air, wherein the second fluid conduit comprises atleast one input connected with each of the first and second outputs ofthe output junction, the second fluid conduit including an outlet toreturn the spent chilled liquid to the cooling plant.
 14. The method ofclaim 13, further comprising controlling, via a manual bypass linevalve, an amount of the portion and the remaining portion of the spentchilled liquid entering the at least one input of the second fluidconduit.
 15. The method of claim 13, further comprising controlling, viaa differential pressure control valve, an amount of the portion and theremaining portion of the spent chilled liquid entering the at least oneinput of the second fluid conduit
 16. The method of claim 13, furthercomprising controlling, via an automatic flow control valve, an amountof the portion and the remaining portion of the spent chilled liquidentering the at least one input of the second fluid conduit.
 17. Themethod of claim 13, further comprising evaluating, via a control system,input data representing one or more variables, and to determine one ormore outputs to control the system to control the one or more variables.18. The method of claim 13, wherein the flow control valve is anautomatic flow control valve.
 19. The method of claim 13, furthercomprising: receiving, via an inlet of a second cooling recovery coil,at least a portion of the spent chilled liquid from the first coolingrecovery coil; and returning, via an outlet of the second coolingrecovery coil, the spent chilled liquid from the second cooling recoverycoil to the cooling plant.
 20. The method of claim 19, furthercomprising modulating, via a variable flow pumping system connected withthe first and second outputs of the output junction, an amount of thespent chilled liquid from the cooling recovery coil to control atemperature of air that passes over the second cooling recovery coil.